Final Version

Table of contents
Program
02
03

Welcome to Quantum Innovation 2022
Organizing Committee

04-06

Symposium Outline

07-09

Program at a Glance

11-12

Quantum Computing Track

Program101314Plenary Sessions

Quantum Cryptography &Communication Track
Quantum Sensing Track
Quantum Sensing Track

15-17

Short Presentations by Young Researchers

18-40

Plenary Sessions

69-88

Quantum Cryptography &Communication Track

Abstract

41-68
89-108Quantum Computing Track
Quantum Sensing Track
Quantum Sensing Track

109-152

Short Presentations by Young Researchers SE-03A

153-180

Short Presentations by Young Researchers SE-03B

Quantum Sensing Track

001

The International Symposium on Quantum Science,
Technology and Innovation
Welcome to Quantum Innovation 2022

It is our pleasure to invite all of you including scientists, engineers, business delegates, young researchers andstudents to Quantum Innovation 2022, the International Symposium on Quantum Science, Technology andInnovation, to be held on 28-30 November 2022 as Virtual Conference.

Quantum Innovation 2022 is the second international symposium hosted by Japanese government andresearch institutes, that aims to bring together multi-disciplined researchers to present and exchange
breaking-through ideas in quantum science and technology.

The topics of Quantum Innovation 2022 cover the latest achievements, trends and needs in quantum scienceand technology including quantum computing, quantum sensing, quantum cryptography and quantum
communication.

We look forward to seeing you in Quantum Innovation 2022 and hope you enjoy excellent presentations fromdistinguished guests, share exciting discoveries and promote fruitful collaborations.

002

Organizing Committee
ChairsGeneral Chair

Kohei Itoh

Keio University

Track Chair
Quantum Computing

Track Chair
Quantum Sensing

Track Chair
Quantum Cryptography & Communication

The University of Tokyo

National Institutes for Quantum
Science and Technology（QST）

National Institute of Information
and Communications Technology（NICT）

Hiroshi Imai

Akinari Yokoya

Masahide Sasaki

Committee members
Keisuke Fujii

Takahiro Mori

Tadashi Sakai

Seiichiro Tani

Takuya Hirano

Takashi Mukaiyama

Yutaka Shikano

Yoshimichi Tanizawa

Tetsuya Ido

Mio Murao

Yutaka Tabuchi

Tokuyuki Teraji

Kae Nemoto

Shuntaro Takeda

Akihisa Tomita

Atsushi Noguchi

Masahiro Takeoka

Hiroshi Yukawa

Shinobu Onoda

Shu Tanaka

Osaka University

Gakushuin University
National Institute ofInformation andCommunications
Technology (NICT)

Takayuki Iwasaki
Tokyo Institute ofTechnology

Kaoru Kenyoshi
National Institute ofInformation andCommunications
Technology (NICT)

Masahiro Kitagawa
Osaka University

National Institute ofAdvanced Industrial Scienceand Technology (AIST)

Osaka University

The University of Tokyo

Okinawa Institute of
Science and Technology
Graduate University (OIST)The University of Tokyo

National Institutes for
Quantum Science andTechnology (QST)

Tokyo Institute ofTechnology

Gunma University
RIKEN

The University of Tokyo

Keio University

Nippon Telegraph andTelephone Corporation (NTT)Toshiba Corporation

National Institute forMaterials Science (NIMS)

Hokkaido University

National Institutes for
Quantum Science andTechnology (QST)

Keio University003

Symposium Outline
Aims

Addressing the state-of-the-art
quantum technology

Exploring cooperation on research,

application, education and social awarenesson quantum technology

We will bring together researchers working on quantum technology and oﬀer a platform fordiscussions among them. Inviting prominent speakers from abroad and Japan, Quantum
Innovation 2022 covers latest development of quantum computing, quantum sensing,quantum cryptography and quantum communication.

We also aim to give young researchers, future quantum working force candidates and aware
citizens an overview of fast evolving quantum technology by listening to inspiring talks.

Scope of the Symposium

Highlights of the development of quantum
technology

Quantum Computing
Quantum Sensing

Quantum Cryptography & Communication

Development of Infrastructure for the progressof quantum technology

Promotion of practical applications of quantum technology
Development of human resources for quantum technology
Promotion of international collaborations

004

Date

28-30 November 2022
Venue

OnlineSchedule
28 November 2022

Plenary Sessions held in Tokyo

29-30 November 2022

Quantum Computing Track
Quantum Sensing Track

Quantum Cryptography & Communication Track

Speakers

All the speakers are to be invited.
Participants
The expected participants include researchers, engineers, business delegates, policy
makers, administrators, students, and the media people, who share interests inquantum technology and innovation.

005

Symposium Sponsors
Cabinet Oﬃce

Ministry of Internal Aﬀairs and Communications (MIC)

Ministry of Education, Culture, Sports, Science and Technology (MEXT)
Ministry of Economy, Trade and Industry (METI)
RIKEN

Japan Science and Technology Agency (JST)National Institutes for Quantum Science and Technology (QST)

National Institute of Advanced Industrial Science and Technology (AIST)

National Institute of Information and Communications Technology (NICT)
Okinawa Institute of Science and Technology Graduate University (OIST)Osaka University

The University of Tokyo
Tohoku University

Tokyo Institute of Technology

Quantum STrategic industry Alliance for Revolution (Q-STAR)

Symposium Supporters
National Institute for Material Science (NIMS)

About QIH

Quantum technology is bringing a great impact on a wide range of industry. In order toaccelerate the progress and make best use of quantum technology, industry, academia
and government are expected to collaborate on promoting basic research, technology
demonstration, industrialization, intellectual property management and humanresource development. For promoting these activities, Japan established Quantum
Technology Innovation Hubs in February 2021.

・Quantum computer development hub in RIKEN

・Global quantum industrial support hub (provisional name) in National Instituteof Advanced Industrial Science and Technology（AIST）

・Quantum computer application hub represented by the University of Tokyo・Quantum software innovation hub in Osaka University
・Quantum security network hub in National Instituteof Information and Communications Technology（NICT）

・Quantum life science and function hub (provisional name) in National Institutes
for Quantum Science and Technology（QST）

・Quantum materials research project in National Institutefor Materials Science（NIMS）

・Quantum sensors hub represented by Tokyo Institute of Technology
・Quantum solution hub (provisional name) in Tohoku University

・International quantum education and research hub (provisional name)in Okinawa Institute of Science and Technology Graduate University (OIST)RIKEN serves as Headquarters of the Hubs to incorporate eﬀorts to advancequantum technology research in Japan.

006

Pr ogr am at a GlanceTracksTracksPL

CP

Plenar y Sessions

Quantum Computing Track

Contents / Topics

Contents / Topics

Welcome from Organizing Committee and Hosts,
Plenary Talks, Keynote

Quantum Computing architecture, Quantum
computers with Atoms and Ions, Photonic Quantum
Computers, Fault Tolerant Quantum Computing,
Quantum Algorithms for Chemistry, NISQ
Algorithms, Young PIs Session, Superconducing
Quantum Computing, Quantum Annealing,
Verifiable Quantum Computing, Semiconductor
Quantum Computers, Quantum Simulations

TracksTracksCC

SE

Quantum Cr yptography &Communication Track

Quantum Sensing Track

Contents / Topics

Contents / Topics

Quantum Internet, Young Researcher Panel Session,
Quantum Cryptography

Q-sensors for Life Science, NV Center and Applications
for Life Sciences, Solid-State Quantum Sensors, 5th
IFQMS Short Presentation Session for Young
Scientists, Solid-State Quantum Sensors, Q-sensors
for Life Science, NV Center and Applications for Life
Sciences, Atom Interferometer, Atom/Ion Clocks *29th
Nov Sessions are a joint-program with The 5th IFQMS(The 5th International Forum on Quantum Metrology
and Sensing).

007

All the times in the program are Japan Standard Time (GMT+�)��
Nov(Mon.)�������:��-��:��

PL-��

Opening��:��-��:��

Vision of Quantum Technology

PL-��

��
��
��

��:��-��:��

Keynote

PL-��

��
��
��

��:��-��:��

Keynote

PL-��

��
��

* �th IFQMS（International Forum on Quantum Metrology and Sensing)��Nov(Tue.)������

�:��-�:���:��-�:���:��-��:��

��:��-��:��

Quantum Computing
Architecture

CP-��

Quantum Computerswith Atoms and Ions �CP-��Photonic Quantum
ComputersCP-��

Fault Tolerant Quantum
ComputingCP-��Quantum Algorithms for
ChemistryCP-��NISQ Algorithms �CP-��Young PIs Session

CP-��

�:��-��:��

Q-Sensors for Life Science,
NV Center and Applications
for Life Sciences

SE-��*

9:00-12:00

Quantum Internet 1

��:��-��:��

Solid-State Quantum Sensors

CC-��

SE-��*

������:��-��:������:��-��:������:��-��:��

��
��
��
��
��

��:��-��:��

Superconducting
Quantum Computing

��:��-��:��

��:��-��:��

Short Presentation
Session for Young
Scientists onSE��, ��, ��, �� Topics[�th IFQMS]

Short Presentation
Session for Young
Scientists onSE��,�� Topics[�th IFQMS]

SE-��A*

13:00-16:00

SE-��B*

Solid-State Quantum Sensors

CC-��

SE-��*

Q-Sensors for Life Science,
NV Center and Applications
for Life Sciences

Quantum
Cryptography �-�
SE-��*

��:��-��:��

Quantum Internet ���:��-��:��
��:��-��:��CC-����:��-��:��

Quantum
Cryptography �-���:��-��:��

CP-��

Young Researcher Session

CC-��

CC-��

��
��
��
��

008

��
Nov

(Wed.)

��:��-��:�����Quantum AnnealingCP-��Veriﬁable Quantum
ComputingCP-����:��-��:����

�:��-��:��Atom Interferometer, Atom/Ion
Clocks

SE-��

��
��
��
��
��
��
��
��

��:��-��:��

��:��-��:��

Semiconductor Quantum
CP-��Computers �

Quantum Simulations

��:��-��:�� Quantum Computing

with Atoms and Ions ���:��-��:�� Semiconductor Quantum
��:��-��:��

Computers �

NISQ Algorithms �CP-����:��-��:��

CP-��
CP-��
CP-��

Quantum Cryptography �-���:��-��:��Atom Interferometer, Atom/Ion
Clocks

SE-��

CC-��

��:��-��:��

Quantum Cryptography �-�

CC-��

��
��
��
��
��

009

Plenary Sessions

All the times in the program are Japan Standard Time(GMT+�)�� N o v(Mon.)

��:��-��:��

Session / Presentation

Chairperson / Presenter

PL-��. Opening
Chairperson

Shigeo Koyasu

RIKEN

Congratulatory Speech

Keitaro Ohno

Parliamentary Association for Quantum Technology Promotion

Welcome��:��-��:��

Aﬃliation

WelcomePL-��. Vision of Quantum Technology
Chairperson

Hideyuki Nakano

Kohei Itoh

Abstract PDF

Parliamentary Vice-Minister of Cabinet Oﬃce

General Chair, Quantum Innovation ���� Organizing Committee

Vision of quantum future society / Future society
to be realized through quantum technology andstrategies for Its realization

Shigeo Koyasu

RIKEN

Kohei Itoh

Chairperson, Strategy Review Working Group on Quantum
Technology and Innovation Strategy, Government of Japan

PL-��-����:��

The national quantum initiative

Gretchen Campbell

Deputy director, the National Quantum Coordination Oﬃce,
OSTP

PL-��-����:��European policy

Gustav Kalbe

Acting Director, Digital Excellence and Science Infrastructure, DG
CONNECT, European Commission

PL-��-����:��

Enabling & growing the quantum industry

Celia Merzbacher

Executive Director, Quantum Economic Development
Consortium (QED-C)

PL-��-����:��

Strengthening Europe's quantum industry on the
global stage

Thierry Botter

Executive Director, Quantum Industry Consortium (QuIC)

PL-��-����:��

Introduction of Q-STAR -Create industries &businesses with quantum technology-

Taro Shimada

Chair of the Board, Quantum STrategic industry Alliance for
Revolution

PL-��-����:��

Promoting Quantum Innovation through thetriangle collaboration

Akihisa Tomita

Chair of Quantum ICT Forum / Hokkaido University

PL-��-����:��

Moonshot Goal �: Realization of a fault-tolerant
universal quantum computer that will revolutionize
economy, industry, and security by ����Masahiro Kitagawa

Program Director of Moonshot#� / Osaka University

PL-��-��

Chairperson

Yasunobu Nakamura

RIKEN

��:��

The next wave of computing: quantum-centric
supercomputing

Jerry ChowIBM

PL-��-����:��

From synchronization to chemical reaction
superpositions

Gregory Scholes

Princeton University

PL-��-����:��Quantum diamond sensors — Best of both worlds Ronald Walsworth

The University of Maryland

PL-��-����:��

Optical quantum computers with quantum
teleportation

Akira Furusawa

The University of Tokyo

PL-��-����:��Quantum computer architecture: from NISQ
processors to fault-tolerant quantum computers

Kae Nemoto

Okinawa Institute of Science and Technology Graduate University

PL-��-����:��How science is becoming and industry

Rupert Ursin

Quantum Technology Laboratories

PL-��-����:��Quantum network technology - the second lifeof rare-earth crystals

Wolfgang Tittel

The University of Geneva

PL-��-����:��

��:��-��:��

PL-��. Keynote

Break (��:�� - ��:��)010

Quantum Computing Track

All the times in the program are Japan Standard Time(GMT+�)�� N o v

Chairperson / Presenter

Aﬃliation

Teruo Tanimoto

Kyushu U

Atsushi Noguchi

UTokyoChairperson

Shuntaro Takeda

UTokyoXanaduCP-��-��

The PhANTM algorithm: measurement-based generation andpreservation of cat and grid states

Olivier Pﬁster

U Virginia

CP-��-��Keisuke Fujii

Osaka U

Chairperson

Keisuke Fujii

Osaka U

Current status of variational quantum algorithms for chemistry andbeyondWataru Mizukami

Osaka U

Hiroshi Imai

UTokyoChairperson

Mio Murao

UTokyo��:��Programmable continuous-variable photonic quantum computing in
the time domain

Shuntaro Takeda

UTokyoCP-��-����:��

Design and optimization of fault-tolerant quantum computing

Yasunari SuzukiNTTCP-��-��Faster emulation of noisy VQE

Tyson JonesU Oxford

CP-��-��

(Tue.)

�:��-�:���:��-�:���:��-��:��

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��:��
��:��

��:��-��:��

Session / Presentation

CP-��. Quantum Computing Architecture
Chairperson

Greater quantum eﬃciency through physics-aware system software
CP-��. Quantum Computers with Atoms and Ions �
Chairperson

Recent advances toward a more capable trapped ion quantum computer
CP-��. Photonic Quantum Computers

Blueprint for a scalable photonic fault-tolerant quantum computer

CP-��. Fault Tolerant Quantum Computing
Chairperson

Suppressing quantum errors by scaling a surface code logical qubit
CP-��. Quantum Algorithms for ChemistryCP-��. NISQ Algorithms �Chairperson

Statistical method for quantum estimation algorithms
CP-��. Young PIs Session

Quantum error correction by low-depth random cliﬀord circuits
CP-��. Superconducting Quantum Computing

Fred Chong

Patty LeeEli Bourassa and Ilan Tzitrin

Zijun Chen

Naoki Yamamoto

Yoshifumi Nakata

U Chicago

Quantinuum

GoogleKeio U

Kyoto U

Abstract PDF

CP-��-��

CP-��-��

CP-��-��

CP-��-��

CP-��-��

CP-��-��

Chairperson

Yutaka Tabuchi

RIKEN
ENS

CP-��-��

��:��

Real-time decoding with a distributed control-stack architecture forfault-tolerant quantum computing

Francesco Battistel

Qblox

CP-��-����:��

Tileable low-crosstalk �D-integrated superconducting circuits

Peter LeekU Oxford

CP-��-����:��

One hundred second bit-ﬂip time in a two-photon dissipative oscillator

Zaki Leghtas

011

Quantum Computing Track

All the times in the program are Japan Standard Time(GMT+�)�� N o v(Wed.)

�:��-��:��

�:��
�:��

Session / Presentation

Chairperson / Presenter

Aﬃliation

Chairperson

Shu Tanaka

Keio U

Search for quantum applications and taking POCs to production

Helmut Katzgraber

AmazonCP-��. Quantum Annealing
Practical quantum computing

Mark Johnson

Abstract PDF

D-WaveCP-��-��

NEC

CP-��-��

CP-��-��Quantum annealer based on kerr parametric oscillators

Tsuyoshi Yamamoto

Chairperson

Seiichiro Tani

NTT

��:��

Bob's sidekick (or how tripartite quantum correlations satisfy a type ofrigidity and how this is useful for cryptography)

Anne Broadbent

U Ottawa

CP-��-����:��

Abstracting quantum computation

Joe Fitzsimons

Horizon Quantum Computing

CP-��-��

Chairperson

Takahiro Mori

AIST

Intel

CP-��-��

Integration of silicon spin qubits with buried nanomagnet: a trial todesign integration structure with quantum device simulator

Shota Iizuka

AISTCP-��-��

Chairperson

Yutaka Shikano

Gunma U
Osaka U

CP-��-��Quantum simulation for quantum many-body systems: variational
quantum algorithms and beyond

Seiji Yunoki

RIKEN

CP-��-��Atsushi Noguchi

UTokyoTakahiro Mori

AIST

Chairperson

Hiroshi Imai

UTokyoAlgorithms and architectures for the ʻLate NISQ’ and ʻEarly FaultTolerant’ Eras

Simon Benjamin

U Oxford

�:����:��-��:��

��:��
��:��-��:��

��:��
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��:��-��:��
��:��
��:��
��:��-��:��

��:��-��:��

��:��-��:��

CP-��. Veriﬁable Quantum Computing

Quantum cryptography without one-way functions
CP-��. Semiconductor Quantum Computers �

From a grain of sand to a |quantum〉bit of information

CP-��. Quantum Simulations
Quantum simulations using phonons in trapped ionsCP-��. Quantum Computing with Atoms and Ions �
Chairperson

Quantum information processing with trapped ionsCP-��. Semiconductor Quantum Computers �Chairperson

Building small, fast and hot hole spin qubits in Si and Ge
CP-��. NISQ Algorithms �Tomoyuki Morimae

James Clarke

Kenji Toyoda

Jonathan Home

Dominik Zumbuhl

Kyoto UETHU BaselCP-��-��

CP-��-��

CP-��-��

CP-��-��

012

Quantum Cryptography & Communication Track
All the times in the program are Japan Standard Time(GMT+�)�� N o v

Chairperson / Presenter

Aﬃliation

Chairperson

TBD

TBD

U Illinois

CC-��-���:��

Generation and manipulation of photonic quantum states forquantum network

Takashi Yamamoto

Osaka U

CC-��-����:��Quantum communication in network channels and multipartite
entanglement distribution

Masahiro Takeoka

Keio U

CC-��-����:��Quantum repeater for continuous-variable entanglement distribution

Josephine Dias

OIST

CC-��-��

Simon Devitt

UTS

Toshihiko Sasaki

UTokyo(Tue.)

�:��-��:��

�:��

��:��

��:��-��:��

Session / Presentation

CC-��. Quantum Internet �
Solid-state quantum emitters for quantum networking

Entanglement distribution for QKD over telecom ﬁber
CC-��. Young Researcher Panel Session

Chairperson

Elizabeth Goldschmidt

Christian Kurtsiefer

Shota Nagayama
David Elkouss

Alexander Ling
��:��-��:��CC-��. Quantum Cryptography �-�Rikizo Ikuta

NUS

Abstract PDF

CC-��-��Keio UOIST
NUS

Osaka U

Chairperson

Akihisa Tomita

Hokkaido U

ID QuantiqueCC-��-����:��Quantum business rising: A new era of investment and wealth creationbuilding the quantum economy

Corey McClelland

Qubitekk

CC-��-����:��Quantum communication at Airbus

Matthieu Dollon

Airbus Defence & Space

CC-��-��Takuya Hirano

Gakushuin U

Paolo Villoresi

U Padova

��:��

��:��

��:��-��:��
��:��-��:��

Quantum key distribution: current applications and future improvements

Information theoretically secure data utilization using "Quantum Secure Cloud"BreakCC-��. Quantum Cryptography �-�Chairperson

Gregoire Ribordy

Mikio Fujiwara

��:��

Field trials and recent activities of QKD research in Toshiba Corporation

Mamiko Kujiraoka

��:��Entanglement distribution and next challenges

Alexander Ling

��:��

��:��

��:��-��:��

��:��
��:��
��:��
��:��

�� N o v(Wed.)

��:��-��:��

Advancements in space quantum communications

Satellite-based QKD for global quantum cryptographic network construction
CC-��. Quantum Internet �
Chairperson

��:��
��:��
��:��
��:��

CC-��-��

ToshibaCC-��-��

NUS

CC-��-��

SKY Perfect JSAT

CC-��-��CC-��-��

TBD

TBD

Resource eﬃcient fault-tolerant one-way quantum repeater with code
concatenation

Johannes Borregaard

TU Delft

CC-��-��Entanglement of trapped-Ion Qubits separated by ��� m

From quantum repeater networks to the quantum internet

Tracy Northup

U InnsbruckCC-��-��Quantum repeaters: Analytical models and optimized protocols

Hideo Kosaka

Peter van LoockU MainzCC-��-��

Session / Presentation

YNU

Chairperson / Presenter

Aﬃliation

Chairperson

Masahide Sasaki

NICT

Panelist �

Dirk Fischer

BSI

Panelist �Masato Koashi

CC-��. Quantum Cryptography �-�Panelist ���:��-��:��

Saori Yokote

NICT

Panelist �
BreakCC-��. Quantum Cryptography �-�

Martin Ward

Yoshimichi Tanizawa
Macros Curty

Toshiba
UTokyoU VigoMasahiro Takeoka

Keio UThe UK quantum communications hub

Tim Spiller

U YorkQuantum communication and cryptography in France

DemoQuanDT: The quantum communication testbed for Germany

Hyungsoo Kim

Eleni Diamanti
Oleg Nikiforov

Abstract PDF

Toshiba

Chairperson

Telco's experience and perspective on quantum cryptography

CC-��-��

KT

CC-��-��

CNRS

CC-��-��DT

CC-��-��CC-��-��

013

Quantum Sensing Track

All the times in the program are Japan Standard Time(GMT+�)��th Nov Sessions are a joint-program with The �th IFQMS (The �th International Forum on Quantum Metrology and Sensing).

�� N o v(Tue.)

�:��-��:��

�:��
�:��
�:��
�:��
��:��-��:��

��:��
��:��
��:��

Session / Presentation

Chairperson / Presenter

Aﬃliation

Chairperson

Hitoshi Ishiwata

QST

Photoactivation of rhodopsins

Hideki Kandori

NITechSE-��. Q-Sensors for Life Science, NV Center and Applications for Life Sciences
Dynamics and mechanism of dimer dissociation of UVR� photoreceptor
How can we measure the quality of consciousness?
Theoretical study on quantum dynamics in condensed phase molecularsystems

SE-��-��

QST

SE-��-��IMS

Chairperson

Hiromitsu Kato

AIST

Hybrid diamond-doped optical ﬁbres for remote magnetometry applications

Brant Gibson

RMIT U

SE-��. Solid-State Quantum Sensors
Quantum sensing and imaging with diamond spins

Quantum sensing by NV centers in diamond semiconductor
SE-��A. Short Presentation Session for Young Scientists on
SE-��,��,��,�� Topics [�th IFQMS]

��:��-��:��

SE-��B. Short Presentation Session for Young Scientists on
SE-��,�� Topics [�th IFQMS]

��:��-��:��

SE-��. Solid-State Quantum Sensors

��:��Makiko Yamada

Ohio State U

Akihito Ishizaki

��:��-��:����:��

Dongping Zhong

Ania Jayich

Norikazu Mizuochi

SE-��-��

SE-��-��

Kyoto U

SE-��-��

Shinobu Onoda

QST

Methods for deterministic production of colour centres in diamond

Jan Meijer

U Leipzig

Mark Newton

SE-��-��UCSB

Chairperson

Controlling and exploiting defects in diamond for quantum technologies

Abstract PDF

SE-��-��

U Warwick

SE-��-��
SE-��-����:��

Synthesis of single crystal diamond with colour centres for quantum
applications

Alexandre Tallaire

CNRS

SE-��-����:��

Introduction to quantum brilliance and its R&D programs

Marcus Doherty

ANU / Quantum Brilliance

SE-��-��

Chairperson

Makoto Negoro

Osaka U

Dissolution dynamic nuclear polarization

Jan Ardenkjar-Larsen

DTU

��:��-��:��

��:��
��:��
��:��

�� N o v

SE-��. Q-Sensors for Life Science, NV Center and Applications for Life Sciences
Hyperpolarized solution-state NMR spectroscopy via quantum resources
Free radical detection in living cells

Romana Schirhagl

NVisionSE-��-��

U Groningen

SE-��-��

SE-��-��

Chairperson / Presenter

Aﬃliation

Chairperson

Tomoya Sato

Tokyo Tech

�:��Keeping the quantum state alive: minute-scale coherence in an atominterferometer

Holger Muller

Stanford U

SE-��-����:��

Toward rotation sensing using a trapped single ion

Takashi Mukaiyama

Osaka U

SE-��-����:��uantum metrology and computing using microscopically-controlled
arrays of alkaline-earths

Adam Kaufman

JILA

SE-��-��

Chairperson

Hidekazu Hachisu

NICT

Exploring quantum gases for terrestrial and space-borne interferometry

Ernst Rasel

LUH(Wed.)

�:��-��:��

��:��

��:��-��:��

��:��
��:��
��:��
��:��

Session / Presentation

Ilai Schwartz

SE-��. Atom Interferometer, Atom/Ion Clocks

Enhanced quantum control for the next generation of optical lattice clocks

SE-��. Atom Interferometer, Atom/Ion Clocks
Quantum sensors with matter waves

A highly charged ion based optical atomic clock

Robust Yb optical lattice clock for contributing to international atomic time

Andrew Ludlow

Philippe Bouyer
Lukas Spies

Masami Yasuda

NIST

Abstract PDF

SE-��-��

U Amsterdam

SE-��-��

PTB

SE-��-��

AIST

SE-��-��
SE-��-��

014

Quantum Sensing Track : Short Presentation Session for Young Scientists
SE-��A. Short Presentation Session for Young Scientists on
SE-��,��,��,�� Topics [�th IFQMS]*Note: Presentation order may change within the same group.
All the times in the program are Japan Standard Time(GMT+�)�� N o v(Tue.)

Session / Presentation

Mentor / Presenter

Aﬃliation

Chair

Ryota Katsumi

TUT

Lock-In detected ramsey magnetometry with a bulk ensemble ofdiamond NV centers for high-sensitivity DC-ﬁeld measurement

Sena Tsuchiya

Tokyo Tech

SE-��A-α�-��

Towards measurement of magnetic ﬁeld generated by the brain of a living
rat using N-V centers in diamond

Naota Sekiguchi

Tokyo Tech

SE-��A-α�-��Identiﬁcation of current multipole sources from magnetoencephalography data

Motofumi Fushimi

UTokyoSE-��A-α�-��Tomoaki Tanaka

QST

SE-��A-α�-��

Spin-dependent photocarrier generation dynamics in electrically detected
NV-based quantum sensor

Hiroki Morishita

Kyoto U

SE-��A-α�-��

Towards nanoscale zero- to ultralow-ﬁeld NMR

Till Lenz

JGU

SE-��A-α�-��Chair

Yuta Kainuma

Tokyo Tech

Extension of dephasing time of ensemble NV centers with a continuousexcitation protocol

Ikuya Fujisaki

Tokyo Tech

SE-��A-β�-��Wide temperature operation of diamond quantum sensor for electricvehicle battery monitoring

Keisuke Kubota

Tokyo Tech

SE-��A-β�-��A development of wearable magnetic shield for MEG

Soichiro Shido

UTokyoSE-��A-β�-��Attempts to generate entanglement state between dipolar coupled NV
centers created by molecular implantation

Kosuke Kimura

QST

SE-��A-β�-��

Charge stability of shallow single NV centers in p-type diamond

Taisuke Kageura

AIST

SE-��A-β�-��

(Near) zero-ﬁeld cross-relaxation features for ensembles of NV centers indiamond

Muhib Omkar

JGU

SE-��A-β�-��

ChairTomoya Sato

Tokyo Tech

Evaluation of a superconducting nanowire single photon detector for
mid-infrared wavelengths

Satoru Mima

NICT

SE-��A-γ�-��*Eﬃcient superconducting nanostrip single-photon detectors for � □mwavelength

Fumihiro China

NICT

SE-��A-γ�-��Eﬀect of pump laser linewidth on nonlinear quantum interferometric fringes Jasleen Kaur

Kyoto U

SE-��A-γ�-��

Highly eﬃcient and ultra-broadband photon pair source using chirped
quasiphase matching slab waveguide matching slab waveguide

Bo CaoKyoto U

SE-��A-γ�-��

Optical trapping and movement control of gold nanoparticles on an optical
nanoﬁberRui SunTohoku U

SE-��A-γ�-��

Electromagnetic-ﬁeld analysis of the plasmon-enhanced single photon
emitters on an optical nanoﬁber

Yining Xuan

Tohoku U

SE-��A-γ�-��

Ultrafast measurement of biphoton wave packets using optical Kerr gating

Takahisa Kuwana

UEC

SE-��A-γ�-����:��-��:��

SE-��A. Short Presentations by Young Researchers on
SE-��, ��, ��, �� Topics [�th IFQMS]

��:��-��:��

SE-��A-α�
Co-chairNaota Sekiguchi

Optimization of simultaneous measurement of magnetic ﬁeld andtemperature measurement by silicon vacancy quantum sensor using
simultaneous resonance��:��-��:��

Dipole-dipole interaction between NV- centers
SE-��A-β�
Co-chairNaoya Morioka

Room-temperature electrical detection of nuclear spins in silicon carbide

��:��-��:��

SE-��A-γ�
Co-chair��:��-��:��

Chikara Shinei

Naoya Morioka

Fumihiro China

SE-��A-α�
Chair

Abstract PDF

Tokyo Tech

NIMS

SE-��A-α�-��Kyoto U

Kyoto U

SE-��A-β�-��

NICTCo-chairRyota Katsumi

Naota Sekiguchi

Tokyo Tech

Growth of thick CVD diamond ﬁlms containing aligned nitrogen-vacancy
centers for high-sensitivity quantum sensors

Takeyuki Tsuji

Tokyo Tech

SE-��A-α�-��Enhancement of ﬂuorescence collection eﬃciency using angle-shaped
diamonds for compact magnetic sensor

Yuta Shigenobu

Tokyo Tech

SE-��A-α�-��TUT

Note: This program was created for fostering young scientists. Presentations with asterisks (*) are excluded from awarding.

015�� N o v

(Tue.)

��:��-��:��

Session / Presentation

Mentor / Presenter

Aﬃliation

Transfer-printing-based integration of SiN grating structure on diamond
toward highly sensitive quantum sensor

Ryota Katsumi

TUT

SE-��A-α�-��

NVC-SPM system to inspect electric devices

Teruo Kohashi

HitachiSE-��A-α�-��*Enhancing sensitivity with entanglement in coupled nitrogen vacancy
centres

Ernst David Herbschleb

Kyoto U

SE-��A-α�-��Frequency-bin generation of entangled photons via quantum opticalsynthesis

Takeru Naito

UEC

SE-��A-α�-��Development of highly sensitive gravimeter based on atom interferometry
using hybrid system for ﬁeld applications

Takeshi Hojo

UEC

SE-��A-α�-��Chair

Naoya Morioka

Kyoto U

Implementation of double quantum magnetometry to continuously
excited ramsey method

Yuta Araki

Tokyo Tech

SE-��A-β�-��

Development of highly sensitive compact quantum sensor with NV centerin ��C-enriched CVD diamond for bio-medical and industrial application

Yuta Kainuma

Tokyo Tech

SE-��A-β�-��

Development of a nonmagnetic helical sensor drive multipoint measuring
mechanism for magnetocardiography in animals

Wenyu Shang

UTokyoSE-��A-β�-��

Ensemble NV- center in diamond for quantum sensing created by highﬂuence electron beam irradiation

Shuya Ishii

QST

SE-��A-β�-��

Synthesis of n-type diamond using tert-butyl phosphine for highsensitivity of the NV sensor

Riku Kawase

Kyoto U

SE-��A-β�-��

Decoherence phenomena in nitrogen-vacancy diamond

Aulden Jones

Georgia Tech

SE-��A-β�-��Chair

Fumihiro China

NICT

Improvement in the long-term stability of the interferometer gyroscopeusing slow and continuous atomic beams

Naoki Nishimura

Tokyo Tech

SE-��A-γ�-��Bragg interferometer using slow and continuous atomic beam with
sub-recoil transverse momentum width

Tomoya Sato

Tokyo Tech

SE-��A-γ�-��*Development of a cryogenic suspension system for TOrsion-Bar Antennae(TOBA)

Ching Pin Ooi

UTokyoSE-��A-γ�-��

Torsion-bar antenna for early earthquake alert

Yuka Oshima

UTokyoSE-��A-γ�-��Optimized Design of Quasi-phase-matched crystal for Spectrally-PureState Generation at MIR Wavelengths Using Metaheuristic Algorithm

Wu-Hao Cai

Tohoku U

SE-��A-γ�-��

Experimental generalized measurement of qubits using a quantum computer

Tingrui Dong

Tohoku U

SE-��A-γ�-��

SE-��A-β�
Co-chair��:��-��:��

Yuta Kainuma

SE-��A-γ�
Co-chairTomoya Sato

Abstract PDF

Tokyo Tech

Tokyo Tech

Note: This program was created for fostering young scientists. Presentations with asterisks (*) are excluded from awarding.

016

Quantum Sensing Track : Short Presentations by Young Researchers
SE-��B. Short Presentation Session for Young Scientists on
SE-��,�� Topics [�th IFQMS]
All the times in the program are Japan Standard Time(GMT+�)�� N o v(Tue.)

Session / Presentation

Mentor / Presenter

Aﬃliation

Chair

Noriaki Yahata

QST

Structural dynamics of the Mn�CaO� cluster during the S�-S� transition inphotosystem II

Hongiie Li

Okayama U

SE-��B-α�-��Visualization of hydrogen in Photosystem II by high-resolution Cryo-EM
analysis

Fusamichi Akita

Okayama U

SE-��B-α�-��Pulsed-EPR study for radical reactions with biological anitioxidants
utilizing quantum eﬀect of electron spin

Hiroki Hirano

Kanagawa U

SE-��B-α�-��Coherent control of radical pair by local optimization theory

Akihiro Tateno

Saitama U

SE-��B-α�-��

Probing the coherent spin dynamics of radical pairs in weak magnetic
ﬁeld using nanoseconds ﬁeld switching technique

Ryusei Nozawa

Saitama U

SE-��B-α�-��Role of tyrosine radical in the photoreaction of the magnetoreceptor
candidate molecule cyptochrome�Hiroaki Otsuka

Waseda U

SE-��B-α�-��Cavity ring-down measurements by continuous pulse trains for magnetic
ﬁeld eﬀects on transient radical species.

Tsubasa Kimura

Saitama U

SE-��B-α�-��Germanium vacancy defects in detonation nanodiamonds for temperaturesensing

Fu Haining

Kyoto U

SE-��B-α�-��Evaluation of the surface-modiﬁed nanodiamond probes by in vivo
ﬂuorescence imaging

Koki Okamoto

Tokyo Tech

SE-��B-α�-��

Detection of heat generation from biological system using double quantum
thermometry

Hitoshi Ishiwata

QST

SE-��B-α�-��The Anomalous Formation of Irradiation Induced Nitrogen-Vacancy
Centers in �-Nanometer-Sized Detonation Nanodiamonds

Frederick Tze Kit SO

Kyoto U

SE-��B-α�-��Microwave antenna architecture for quantitative prediction of ODMR signals

Keisuke Oshimi

Okayama U

SE-��B-α�-��ChairYoichi Takakusagi

QST

An Artiﬁcial Intelligence Nanopore Platform Detects Mutant SARS-CoV-�
including Omicron Variant by Recognizing Spike Proteins

Kaoru Murakami

Hokkaido U

SE-��B-α�-��Non-equilibrium phi� theory in a Hierarchy: Towards Manipulating
Holograms in Quantum Brain Dynamics

Akihiro Nishiyama

Kobe U

SE-��B-α�-��

Construction of dipeptide-based DNP-NMR molecular probe libraryfocusing on kidney injury mouse model

Yuki Aketa

U TokyoSE-��B-α�-��

Nuclear hyperpolarization of liquid water by using photoexcited triplet
electrons in organic nanocrystals

Naoto Matsumoto

Kyushu U

SE-��B-α�-��

Molecular development for highly eﬃcient Triplet-DNP

Keita Sakamoto

Kyushu U

SE-��B-α�-��

DNP-NMR molecular probe for the detection of Dipeptidyl peptidase-�
activity in vivo

Akihito Goto

U TokyoSE-��B-α�-��Generation of polarized triplet electron spins at solid-liquid interfaces

Reiya Yabuki

Kyushu U

SE-��B-α�-��

Photoreaction study of a primate blue-light sensitive photoreceptor using
vibrational spectroscopy

Yosuke Mizuno

NITechSE-��B-α�-��

Novel photoisomerization reaction in near-infrared light absorbing
enzymerhodopsins

Masahiro Sugiura

NITechSE-��B-α�-��Development of single-shot �D temperature imaging system for real-timeobservation of thermal diﬀusion in vivo

Haruka Maeoka

Hiroshima U

SE-��B-α�-��Bidirectional neural network and its application to image denoising,super-resolution, and image completion

Kei Majima

QST

SE-��B-α�-��Understanding of protein functional expression using hybrid QM/MM
molecular simulation

Masahiko Taguchi

QST

SE-��B-α�-����:��-��:��

SE-��B. Short Presentation Session for Young Scientists on
SE-��,�� Topics [�th IFQMS]

��:��-��:��

SE-��B-α�.
Co-chair��:��-��:��

SE-��B-α�.
Co-chair

Hidetoshi Kono

Ryoko Araki

Abstract PDF

QST

QST

017

A bst r act

TracksTracksPL

CP

Plenar y Sessions

Quantum Computing Track

Contents / Topics

Contents / Topics

Welcome from Organizing Committee and Hosts,
Plenary Talks, Keynote

Quantum Computing architecture, Quantum
computers with Atoms and Ions, Photonic Quantum
Computers, Fault Tolerant Quantum Computing,
Quantum Algorithms for Chemistry, NISQ
Algorithms, Young PIs Session, Superconducing
Quantum Computing, Quantum Annealing,
Verifiable Quantum Computing, Semiconductor
Quantum Computers, Quantum Simulations

TracksTracksCC

SE

Quantum Cr yptography &Communication Track

Quantum Sensing Track

Contents / Topics

Contents / Topics

Quantum Internet, Young Researcher Panel Session,
Quantum Cryptography

Q-sensors for Life Science, NV Center and Applications
for Life Sciences, Solid-State Quantum Sensors, 5th
IFQMS Short Presentation Session for Young
Scientists, Solid-State Quantum Sensors, Q-sensors
for Life Science, NV Center and Applications for Life
Sciences, Atom Interferometer, Atom/Ion Clocks *29th
Nov Sessions are a joint-program with The 5th IFQMS(The 5th International Forum on Quantum Metrology
and Sensing).

018

PL-02-01

Quantum technology policy in Japan
Kohei Itoh
Keio University

Biography
President Kohei Itoh graduated from Keio University and received his M.
S. and Ph. D. in Engineering from University of California, Berkeley. He
joined Keio University as a faculty member in 1995 and became a full
professor in 2007. He served as Dean of Faculty and Graduate School of
Science and Technology of Keio University between 2017 and 2019, and as
the Chair of Keio AI and Advanced Programming Consortium between
2018 and 2021. His main focus of research has been quantum computing,quantum sensing, and quantum physics, which led to more than
330 journal publications. He is one of 210 Council Members of Science
Council of Japan representing ~870,000 scholars of the country to
propose and advice academic and scientific policies in Japan, and has
served on numerous executive boards including the Physical Society ofJapan and the Japan Society of Applied Physics. He leads the Program
Director of Quantum Information Technology in the MEXT Quantum Leap
Flagship Program for researchers representing the field. He is a recipientof the Japan IBM Prize (2006) and the JSPS (Japan Society for the
Promotion of Science) Prize (2009). He is also a founder of the IBM
Quantum Computer Network Hub at Keio University.

Abstract
In January 2020, Japanese Government compiled the “Quantum
Technology and Innovation Strategy,” which formed the basis of policies
to enhance research and development of quantum technology in Japan.
Thanks to this initiative, Japan has been able to invest significant

019

amounts of financial and human resources to stay as one of the main
players of quantum innovation in the world. In order to accelerate such
effort even further, in March 2022, Japanese government has announced
the “ Vision of Quantum Future Society,” that aims to enable a social
reform through quantum technology. This presentation overviews an
overall policy of Japan on quantum technology research anddevelopment.

020

PL-02-02

The national quantum initiative
Gretchen Campbell
National Quantum Coordination Office, OSTP

Biography
Gretchen Campbell is the Deputy Director for the National Quantum
Coordination Office at the White House Office of Science and Technology
Policy, where she helps coordinate QIS programs across the Federal
Government. Campbell is on detail from the National Institute ofStandards and Technology (NIST), where she is the co-director of the
Joint Quantum Institute, a joint institute between the University of
Maryland and NIST, and the Group Leader for the Laser Cooling andTrapping group in the Quantum Measurement Division at NIST. She isalso an Adjunct Professor in the Department of Physics at the Universityof Maryland. Dr. Campbell received a B.A. in Physics from Wellesley
College in 2001 and received her Ph.D. from MIT in 2007. From 2007-2009,
she was a NRC postdoctoral fellow at JILA and NIST in Boulder, Colorado.
Dr. Campbell’s research has included a wide range of experimental workin the field of ultracold atomic gases. She is a fellow of the American
Physical Society. Her awards include the Arthur Flemming Award (2012);
the Presidential Early Career Award in Science and Engineering (2012);
the Sigma Xi Katherine Blodgett Gebbie Young Scientist Award (2013); the
APS Maria Goeppert Mayer Award (2015), and the IUPAP C15 Young
Scientist Prize (2015). She was also a Finalist for the Samuel J. Heyman
Service to America Medals, Call to Service category (2015).

Abstract
In 2018, the United States launched the National Quantum Initiative (NQI)
to accelerate research and development (R&D) in quantum information

021

science (QIS) within the United States. Since then, the U.S. has been
advancing QIS by getting the science right, enhancing competitiveness,and enabling people. For science, the NQI Act authorized U.S. Federal
departments and agencies to establish centers to address the mostpressing scientific frontiers in QIS. To enhance competitiveness, the U.S.
has engaged industry and international partners to drive QIS technology
development toward useful applications, while also protecting national
security. To enable people, the U.S. is building the QIS workforce andconducting outreach to create new opportunities.

022

PL-02-03

European policy
Gustav KALBE
European Commission

Biography
Dr. Gustav Kalbe is German, born in Belgium. From 1986 to 1990 hestudied Applied Physics at the Université Catholique de Louvain,
Belgium. In 1991 he studied Applied Optics at the Imperial College of
Science in London. In 1995 he completed his studies and earned a PhD in
Physics, Molecular Spectroscopy, at the Université Catholique deLouvain, Belgium.
He started his professional career as a project manager in photonic
networks at the incumbent telecom operator in Belgium. He was R&D
manager when he left the company.
In 1998 he joined the Directorate General Information Society & Media of
the European Commission where he started working as Project Officer
managing research projects of the European Framework Programs for
Research. Over the years he had several assignments in quantum
technologies, photonics, and cybersecurity.
In 2014 Gustav Kalbe became Head of Unit for Administration & Financein the European Commission, in Directorate General Communications
Networks, Content and Technology.
In 2016 he was appointed Head of Unit of the newly created High
Performance Computing and Quantum Technology unit in Directorate
General Communications Networks, Content and Technology.
In 2018 he became responsible for the establishment and operation of
the European High Performance Computing Joint Undertaking. He
occupied the post of Interim Executive Director of the Joint Undertaking
until its autonomy by the end of 2020.
In January 2021, he was appointed Deputy to the Director of DG Connect
C “Digital Excellence and Science Infrastructure”.
Since May 2022 Gustav is the Acting Director of DG Connect C “Digital023

Excellence and Science Infrastructure”.

Abstract
I will introduce the European activities and policy approach in Quantum
Technologies, starting with the Quantum Technologies Flagship andsome of its successes during its ramp-up phase (2018-2021). I will thenpresent the vision and avenues for Europeʼs digital transformation by
2030, as proposed in 2021 by the European Commission in the Europeʼs
Digital Decade, pursuing the ambition to reach a first European computerwith quantum acceleration by 2025. Following this vision, the European
policy approach to quantum has naturally transitioned towards higher
technical maturity with the deployment of quantum-based
infrastructures. In this context, first I will introduce the pilot lines(factories) for advanced quantum chip production (so-called “ fabs”) as
one of the new instruments of the European Chips Act, then I will present
the European Quantum Communication Infrastructure (EuroQCI)Initiative aiming at building a secure quantum communication
infrastructure that will span the whole EU. Finally, I will present theEuropean High-Performance Computing Joint Undertaking (EuroHPC JU)
and its roadmap to quantum computing deployment including the recent
selection of six sites that will host the first European quantum computers,with a view on the Japan-EU Digital Partnership established in Spring
2022.

024

PL-02-04

Enabling & growing the quantum industry
Celia Merzbacher
Executive Director, Quantum Economic Development Consortium (QED-C)

Biography
Dr. Celia Merzbacher, QED-C Executive Director

Abstract
The Quantum Economic Development Consortium (QED-C) is a
consortium of stakeholders that aims to enable and grow the U.S.
quantum industry.

025

PL-02-05

Strengthening Europe’s quantum industry on
the global stage
Thierry Botter
Executive Director, Quantum Industry Consortium (QuIC)

Biography
Dr. Thierry Botter, Executive Director, European Quantum Industry
Consortium (QuIC)

Abstract
Overview presentation of the European Quantum Industry Consortium(QuIC), Europe’s largest and most influential quantum industry group.

026

PL-02-06

Introduction of Q-STAR -Create industries &businesses with quantum technologyTaro Shimada
Quantum STrategic industry Alliance for Revolution (Q-STAR)

Biography
Taro Shimada joined Toshiba in October 2018 as Corporate Digital
Business Chief Strategy Officer. He has served as Chief Digital Officer,
responsible for supporting Toshiba’s digital transformation andspearheading strategic business creation and promotion, since April
2019. He was appointed CEO & Representative Director of Toshiba Data
Corporation in February 2020, and President and CEO of Toshiba Digital
Solutions Corporation in April 2020. In March 2022, Mr. Shimada was
appointed to take the reins at Toshiba, as President & CEO.
Mr. Shimada has a diverse background in hardware development,
including commercial aircraft; in process consultation, ranging fromautomobiles to precision machinery design and heavy industry; and in
product life cycle management software. As an expert in Factory
Automation, he advised many of Japan’s leading global manufacturers
on digitization, and he remains an advisor to the Robot Revolution &Industrial IoT Initiative, and to the IoT Acceleration Lab. He has also
contributed to the activities of Industrie 4.0 in Germany and Connected
Industries in Japan.
Mr. Shimada began his career in1990 at ShinMaywa Industries Kobe,
where he worked on aircraft for Boeing and McDonnell Douglas. In 1999
he joined Structural Dynamics Research Corporation, a part of Siemens,
and took on a series of progressively senior post at Siemens KK, and at
Siemens HQ in Germany. Immediately prior to joining Toshiba, Mr.
Shimada was Executive Operating Officer at Siemens K.K. He has been aguest professor at Otemon Gakuin University in Osaka, Japan, since April
2020. In May 2022, he was appointed Chairman of Q-STAR (Quantum
027

STrategic industry Alliance for Revolution), a consortium that promotes
business creation with quantum technologies.
Away from the office Mr. Shimada relaxes by playing the drums, andenjoys all genres of music.

Abstract
As quantum technologies start the shift from R&D to commercialization,
there are several areas where advances are required.
These are discussed in an overview of recent trends in quantum
technology.
The latter half of the presentation introduces Q-STAR.
Now a general incorporated association, Q-STAR is accelerating its efforts
to create new quantum businesses.
The presentation discusses how these activities support Q-STAR’s goal ofcontributing to a future society where quantum technology is taken for
granted.

028

PL-02-07

Promoting Quantum Innovation through thetriangle collaboration
Akihisa Tomita
Quantum ICT Forum / Hokkaido University

Biography
Akihisa Tomita received the B.S. and M.S. degrees in physics and the
Ph.D. degree in electronics from the University of Tokyo in 1982, 1984
and 1998, respectively. He engaged in the research on photonics from1984 to 2000 and conducted research on quantum information
technology from 1998 to 2010 both in NEC Corporation. He also led thegroup for quantum information experiments in Quantum Computation
and Information Project, ERATO and SORST, JST, from 2000 to 2010. He isa professor at Faculty of Information Science and Technology, Hokkaido
University since 2010. His current research covers photonics for quantum
information processing and quantum communication.

Abstract
To create a sophisticated society, it is required to establish efficient
processing and analysis of large quantities of data collected from various
places, decision of the optimum actions, and accomplishment of theorder sent from the artificial intelligence. Highly sensitive and highly
accurate sensors, high-speed computers, and communications with low
latency and guaranteed security are thus necessary. Quantum
information and communication technology (ICT) is a radical solution tothese challenges. Though the potential of quantum ICT was alreadyknown from the mid 1980s to 2000s, its realization has long been inquestion. However, Quantum ICT has come to be recognized worldwide
as an emerging technology in the foreseeable future, rather than a029

technology that may or may not be realized. Quantum ICT Forum (QICTF)
was established to bring innovation in the quantum technology and tocontribute to the realization of a creative society by working on thedevelopment and diffusion of quantum ICT. In this talk, I will review thescientific and industrial activities on quantum ICT in Japan shortly. Then,
I will present efforts to encourage the triangle collaboration between theindustry, government, and academia.

030

PL-02-08

Moonshot Goal 6: Realization of a fault-tolerant
universal quantum computer that will
revolutionize economy, industry, and securityby 2050
Masahiro Kitagawa
Japan Science and Technology Agency / Osaka University

Biography
Dr. Masahiro Kitagawa is a Professor of Graduate School of Engineering
Science https://www.es.osaka-u.ac.jp/en/ and the director of Center for
Quantum Information and Quantum Biology https://qiqb.osaka-u.ac.jp/
en/, Osaka University. He received BEng in ’81, MEng in ’83, and Ph.D. inquantum physics in ’94 from Osaka University. He was a researchscientist at NTT Basic Research Laboratories from ’83 to ’93. He has beenworking on quantum optics and quantum information since ’85. He has
been a faculty member of Osaka University since ’93 and a Professor
since ’03. He has served as Research Director of JST/CREST Projects;
Nuclear Spin Network Quantum Computers (’99-05), Molecular Spin
Quantum Computers (’05-11), and, Hypersensitive MRI/NMR by means ofRoom Temperature Hyperpolarization and Quantum Coding (’16-22). His
research interest covers quantum measurement and sensing, quantum
communications, quantum computing, and, quantum biology. He serves
as the program director of the Moonshot Goal 6 toward fault-tolerant
universal quantum computer https://www.jst.go.jp/moonshot/en/
program/goal6/, the project leader of the Quantum Software Research
Hub http://qsrh.jp/ and a member of the quantum innovation committeeof the cabinet office since ’20. He is a co-founder of QunaSys Inc. https://en.qunasys.com, a quantum software startup, and QuEL Inc. https://quelinc.com, a quantum middleware startup. His paper on “Squeezed Spin
States” is selected as Physical Review A 50th Anniversary Milestones
https://journals.aps.org/pra/50th. He is a life member of American031

Physical Society and a member of Physical Society of Japan.

Abstract
Moonshot goal 6 is an ambitious and challenging program towards faulttolerant universal quantum computer. The strategy and the portfolio of
the program, and, the project managers and their projects will be
introduced. The moonshot international symposium to be held next Julyin Tokyo will be announced.

032

PL-03-01

The next wave of computing: quantum-centric
supercomputing
Jerry Chow
IBM Quantum

Biography
Dr. Jerry M. Chow is an IBM Fellow and the Director of Quantum
Infrastructure at IBM leading the effort to envision and implement IBM'squantum hardware roadmap encompassing technology,
characterization, and system integration. His technical expertise is in thearea of superconducting qubits quantum computing. Chow graduatedmagna cum laude with a BA in physics and MS in applied mathematics
from Harvard University (2005) and subsequently a PhD in physics fromYale University (2010). He joined IBM as a Research Staff Member in 2010.
In 2016 he co-lead the IBM Quantum Experience project, placing a realquantum processor accessible to anyone on the Cloud. In 2021, he wasnamed an APS Fellow in the Division of Quantum Information andreceived the Yale Science and Engineering Association Award for
Advancement of Basic and Applied Science.

Abstract
The last few years have witnessed a strong evolution in quantum
computing technologies, moving from research labs to an unprecedented
access by the general public via the cloud. Recent progress in quantum
processor size, speed, and quality, have cleared the picture towards along-term vision in computing, where quantum processors will play a keyrole in extending the computational reach of supercomputers. In this talkI will describe how modularity will enable scaling, and how quantum
communication will increase computational capacity. All thisorchestrated by a hybrid cloud middleware for quantum for seamlessintegration of classical and quantum workflows in an architectural
construct that we call quantum-centric supercomputer.
033

PL-03-02

From synchronization to chemical reaction
superpositions
Gregory D Scholes
Princeton University

Biography
Greg Scholes is the William S. Tod Professor of Chemistry and Chair ofDepartment at Princeton University. This year he was selected as aninaugural Ivy+ Provost Leadership Fellow with the goal of helping toadvance diversity and inclusion in the American professoriate. Originallyfrom Melbourne, Australia, he later undertook postdoctoral training at
Imperial College London and University of California Berkeley. He started
his independent career at the University of Toronto (2000-2014) where he
was the D.J. LeRoy Distinguished Professor. He was appointed Editor-inChief of the Journal of Physical Chemistry Letters in 2019. Dr. Scholes waselected a Fellow of the Royal Society (London) in 2019 and a Fellow of theRoyal Society of Canada in 2009.

Abstract
Synchronization abounds in nature-why is it so hard to synchronize
quantum systems? I will discuss this general question and its relationshipto quantum coherence and exciton delocalization. I will then report newexperiments that show how a molecular exciton state can launch two asuperposition of two chemical reactions. Specifically, we study
femtosecond proton transfer in a symmetric molecule with two identical
reactant sites that are spatially apart. With the reaction launched from asuperposition of two local basis states, we hypothesize that the motionsof the electrons and nuclei will ensue in lock-step as a superposition ofprobability amplitudes until decoherence collapses the system to a
product. We see evidence for this, and conclude that this chemicalsystem is a good test-bed to study the transition from quantum toclassical.
034

PL-03-03

Quantum diamond sensors — Best of bothworldsRonald Walsworth
University of Maryland

Biography
Ronald Walsworth is a Minta Martin Professor in the Department of
Physics and in the Department of Electrical and Computer Engineering at
the University of Maryland (UMD). He is also the Founding Director of the
Quantum Technology Center (QTC) at UMD, which focuses on thedevelopment and translational applications of quantum science, as wellas education of the quantum technology workforce.

Abstract
The nitrogen–vacancy (NV) quantum defect in diamond is a leading
modality for magnetic, electrical, temperature, and force sensing withhigh spatial resolution and wide field-of-view under ambient conditions.
This quantum sensing technology has diverse applications across thephysical and life sciences — from probing magnetic materials to imaging
integrated circuit activity to biomedical diagnostics. I will provide an
overview of quantum diamond sensors and their many applications; andoutline paths toward improved performance and utility.

035

PL-03-05

Optical quantum computers with quantum
teleportation
Akira Furusawa
The University of Tokyo / RIKEN

Biography
Akira Furusawa received his MS degree in applied physics and Ph.D.
degree in physical chemistry from The University of Tokyo, Japan, in 1986
and 1991, respectively. His research interests cover the area of nonlinear
optics, quantum optics, and quantum information science. He is currently
Professor of Applied Physics, School of Engineering, The University ofTokyo and the Deputy Director of RIKEN Center for Quantum Computing.
Professor Furusawa has authored more than 100 papers in leading
technical journals and conferences, which include the first realization of
unconditional quantum teleportation, which was achieved in 1998 at
California Institute of Technology as a visiting scientist at Professor Jeff
Kimble’s lab. He received the Ryogo Kubo Memorial Award in 2006, theJSPS prize in 2007, the Japan Academy Medal in 2007, the International
Quantum Communication Award in 2008, the Toray Science andTechnology prize in 2015, and the Medal with purple ribbon in 2016. He isa member of the Physical Society of Japan, the Japanese Society ofApplied Physics, and OPTICA.

Abstract
We did the first experiment of unconditional quantum teleportation at
Caltech in 1998 [1]. Then we did various related experiments likequantum teleportation network [2], teleportation of Schrödinger’s cat
state [3], and deterministic quantum teleportation of photonic qubits [4].
We invented the scheme of teleportation-based quantum computing in036

2013 [5]. In this scheme, we can multiplex quantum information in the time
domain and we can build a large-scale optical quantum computer onlywith four squeezers, five beam splitters, and two optical delay lines [6].
Our present goal is to build a super quantum computer with 100GHz
clock frequency and hundred cores. Toward this goal we started to
combine our optical quantum computer with 5G technologies [7].
1. A. Furusawa et al., Science 282, 706 (1998).
2. H. Yonezawa et al., Nature 431, 430 (2004).
3. N. Lee et al., Science 332, 330 (2011).
4. S. Takeda et al., Nature 500, 315 (2013).
5. S. Yokoyama et al., Nature Photonics 7, 982 (2013).
6. W. Asavanant et al., Science 366, 375 (2019).
7. A. Inoue et al., arXiv:2205.14061 [quant-ph]037

PL-03-07

How science is becoming and industry
Rupert Ursin
qtlabs GmbH

Biography
Dr. Rupert Ursin is co-founder of qtlabs GmbH. He has 20+ years researchexperience in quantum communication at the Austrian Academy of
Science. His scientific publication describe ground breaking experiments
at the time and are among the highest cited in the field – still today. His
research focus is the development of quantum communication andquantum information processing technologies, especially for free spacetransmission up to satellites, but also for fiber-based systems. Aims of his
work range from short-term engineering solutions for secure key
partitioning (quantum cryptography) to speculative research (quantum
teleportation and entanglement swapping). He is now CEO at thecompany he founded with his former postDoc Thomas Scheidl who is
now CTO and CEO of qtlabs GmbH. qtlabs is doing R&D and prototypingof quantum technologies aimed at performing full scale QKD fromsatellites and through optical fibers; first products include, besides thetasks as aquantum engineering firm for architecture, design andsimulation of quantum networks, optical ground receivers for quantum
states.

Abstract
Quantum Physics originated from very deep questions about the natureof reality and locality. Only in the 80’s it turned out, that might become
the basis of a new kind of technology – today called quantum technology.
In my presentation I will show my personal journey from experiments
about basic interest in academia up to a research group leader and deputy

038

director at the Austrian Academy of Sciences here in Vienna. Just recently
I quit my permanent position to become a full-time entrepreneur, now
developing products for the so-called quantum technology revolution. I’ll
present the ecosystem, including a Chinese satellite mission MICIUS,
we’ve been part of, to the European quantum Programs, the demand
from the finance- and critical-infrastructure industry and the products
we are developing, both for space and terrestrial applications.

039

PL-03-08

Quantum network technology - the second lifeof rare-earth crystals
Tittel Wolfgang
University of Geneva, Delft Technical University, Schaffhausen Institute of Technology

Abstract
Starting with the demonstration of lasing more than 50 years ago, thespecial properties of rare-earth crystals and glasses have enabled thedevelopment of numerous solid-state lasers and amplifiers, which are
crucial for the functioning of today’s Internet. As a fascinating
generalization of their use in optical communication infrastructure, it
became clear during the past decade that, when cooled to a few Kelvin,rare-earth crystals also promise the creation of technology for quantum
communication networks.
I will discuss recent advances towards the development of key
ingredients of such networks: the creation of single photons using
individual rare-earth ions coupled to nano-photonic cavities, as well as
the reversible storage of quantum states of light in large ensembles ofrare-earth ions. This work is not only interesting from a fundamental
point of view, but furthermore paves the path towards a quantum
repeater, which will ultimately enable quantum communications overarbitrary distances.

040

A bst r act

TracksTracksPL

CP

Plenar y Sessions

Quantum Computing Track

Contents / Topics

Contents / Topics

Welcome from Organizing Committee and Hosts,
Plenary Talks, Keynote

Quantum Computing architecture, Quantum
computers with Atoms and Ions, Photonic Quantum
Computers, Fault Tolerant Quantum Computing,
Quantum Algorithms for Chemistry, NISQ
Algorithms, Young PIs Session, Superconducing
Quantum Computing, Quantum Annealing,
Verifiable Quantum Computing, Semiconductor
Quantum Computers, Quantum Simulations

TracksTracksCC

SE

Quantum Cr yptography &Communication Track

Quantum Sensing Track

Contents / Topics

Contents / Topics

Quantum Internet, Young Researcher Panel Session,
Quantum Cryptography

Q-sensors for Life Science, NV Center and Applications
for Life Sciences, Solid-State Quantum Sensors, 5th
IFQMS Short Presentation Session for Young
Scientists, Solid-State Quantum Sensors, Q-sensors
for Life Science, NV Center and Applications for Life
Sciences, Atom Interferometer, Atom/Ion Clocks *29th
Nov Sessions are a joint-program with The 5th IFQMS(The 5th International Forum on Quantum Metrology
and Sensing).

041

CP-01-01

Greater quantum efficiency through physicsaware system software
Chong Fred
University of Chicago / ColdQuantaAbstract
Quantum computing is at an inflection point, where 127-qubit machines
are deployed, and 1000-qubit machines are perhaps only a few years
away. These machines have the potential to fundamentally change ourconcept of what is computable and demonstrate practical applications inareas such as quantum chemistry, optimization, and quantum
simulation.
Yet a significant resource gap remains between practical quantum
algorithms and real machines. A promising approach to closing this gap
is to design software that is aware of the key physical properties of
emerging quantum technologies. I will illustrate this approach with someof our recent work that focuses on techniques that break traditional
abstractions and inform hardware design, including compiling programs
directly to analog control pulses, computing with ternary quantum bits,
2.5D architectures for surface codes, and exploiting long-distancecommunication and tolerating atom loss in neutral-atom machines.

042

CP-02-01

Recent advances toward a more capabletrapped ion quantum computer
Patty Lee
Quantinuum

Abstract
Critical applications of quantum computation require higher
performance than todayʼs quantum computers can provide. Towards
that end, Quantinuum has continued to improve the performance of
H-Series quantum computers in the past year, by increasing the fidelity ofquantum operations and the number of qubits in H1 systems, to achievea Quantum Volume of 8192. With the updated hybrid computing feature,
we embarked on fault-tolerant quantum computing by entangling two
logical qubits on H1. Additional breakthroughs including junction
transport, state preparation and measurement fidelity improvements,
and a qubit re-use compiler pave the way to scaling up to larger andmore capable quantum computers.

043

CP-03-01

Blueprint for a scalable photonic fault-tolerant
quantum computer
J. Eli Bourassa
XanaduAbstract
This talk will present Xanaduʼs proposal for a scalable and fault-tolerant
photonic quantum computer. Central to the architecture are GottesmanKitaev-Preskill bosonic qubits and squeezed states of light, stitched
together into a qubit cluster state with one time and two spatial
dimensions. This proposal for generating and manipulating a 3D resource
state for fault-tolerant, measurement-based quantum computation
combines state-of-the-art proposals for the preparation of bosonicqubits with the strengths of continuous-variable quantum computation
performed using easy-to-generate squeezed states. Moreover, thearchitecture is based on modular, easy-to-network integrated photonic
chips, opening the door to scalable fabrication and operation.

044

CP-03-02

The PhANTM algorithm: measurement-based
generation and preservation of cat and gridstatesOlivier Pfister
University of Virginia

Abstract
We present an algorithm to reliably generate various quantum states
critical to quantum error correction and universal continuous-variable(CV) quantum computing, such as Schrödinger cat states and GottesmanKitaev-Preskill (GKP) grid states, out of Gaussian CV cluster states. Ouralgorithm is based on the Photon-counting-Assisted Node-Teleportation
Method (PhANTM), which uses standard Gaussian information processing
on the cluster state with only the addition of local photon-numberresolving measurements. We show that PhANTM can apply polynomial
gates and embed cat states within the cluster. This method also stabilizes
cat states against Gaussian noise and perpetuates non-Gaussianity
within the cluster. Finally, we show that existing protocols for breeding
cat states can be embedded into cluster state processing using PhANTM.

045

CP-04-01

Suppressing quantum errors by scaling asurface code logical qubit
Zijun Chen
Google Quantum AI

Abstract
Practical quantum computing will require error rates that are well below
what is achievable with physical qubits. Quantum error correction offersa path to algorithmically-relevant error rates by encoding logical qubits
within many physical qubits, where increasing the number of physicalqubits enhances protection against physical errors. However, introducing
more qubits also increases the number of error sources, so the density oferrors must be sufficiently low in order for logical performance toimprove with increasing code size. In this talk, I will discuss recent workmeasuring logical qubit performance scaling across multiple code sizes,
and demonstrate that our system of superconducting qubits has
sufficient performance to overcome the additional errors from increasing
qubit number. We find our distance-5 surface code logical qubit modestly
outperforms an ensemble of distance-3 logical qubits on average, both interms of logical error probability over 25 cycles and logical error per
cycle. We are able to accurately model our experiment, and from thismodel we can extract error budgets that highlight the biggest challenges
for future systems. These results mark the first experimental
demonstration where quantum error correction begins to improve
performance with increasing qubit number, illuminating the path toreaching the logical error rates required for computation.

046

CP-05-02

Current status of variational quantum
algorithms for chemistry and beyond
Wataru Mizukami
Center for Quantum Information and Quantum Biology, Osaka Univ., Japan

Abstract
Quantum chemistry has been seen as a promising application for
quantum computers so far. Driven by this expectation, the developmentof algorithms for quantum chemistry using quantum computers has been
active over the past five years. As a result, variational quantum
algorithms (VQAs) can now be used to perform a wide range of chemical
calculations with quantum circuit emulators. Such state-of-the-art VQAs
have been implemented in various open-source software and cloudservices and are readily available to anyone. On the other hand, thechallenges for the practical application of quantum chemical calculations
using real quantum computers are becoming increasingly clearer. In thistalk, I will first introduce our progress in quantum chemical calculations
using VQA. Next, I will introduce 1) our recently-proposed perturbation
theory using quantum signal processing [arXiv:2210.00718] and 2)
resource estimation for phase estimation for model Hamiltonians[arXiv:2210.14109], respectively, and discuss challenges that lie ahead.

047

CP-06-01

Statistical method for quantum estimation
algorithms
Naoki Yamamoto
Keio University

Abstract
In this talk I will present some quantum algorithms that incorporate
statistical methods for lowering the required number of entangling gates
as well as the number of qubits, while maintaining quantum advantage
to estimate target quantities. As a particular example, I will present thequantum-enhanced mean-value estimation algorithm; namely, thequantum algorithm for estimating the mean value of physicalobservables with less number of queries compared to the conventional
approach.

048

CP-07-01

Programmable continuous-variable photonic
quantum computing in the time domain
Shuntaro Takeda
The University of Tokyo

Abstract
Photonic quantum computing has recently been dramatically scaled up,
demonstrating quantum supremacy and large-scale entangled state
generation. Such progress has been made by an approach combining
continuous-variable and multiplexing schemes. The continuous-variable
scheme offers more efficient quantum light sources and detectors than
the traditional qubit-based scheme. On the other hand, the multiplexing
schemes in time, frequency, and spatial modes enable us to scale up
quantum computation in compact photonic circuits. The combination ofthese schemes is a promising route to large-scale quantum computers.
We are pursuing programmable and scalable photonic quantum
computers based on the continuous-variable and time-multiplexing
schemes. In particular, we proposed a loop-based photonic quantum
computing architecture where a single quantum processor sequentiallyperforms gates on time-multiplexed optical pulses arranged in a loop
(Physical Review Letters 119, 120504 (2017)). In this talk, we introduce ourrecent development in this direction, including the demonstration of aprogrammable multi-step quantum processor (Science Advances 7,
eabj6624 (2021)), the development of a programmable time-multiplexed
quantum light source (arXiv:2209.09458), and the implementation of aquantum algorithm using a programmable photonic circuit(arXiv:2206.07214).

049

CP-07-02

Design and optimization of fault-tolerant
quantum computing
Yasunari Suzuki
Nippon Telegraph and Telephone Corporation

Abstract
While fault-tolerant quantum computing (FTQC) is considered the mostpromising way to achieve reliable quantum computing, it demands theintegration of high-fidelity physical qubits and the complicated design oflogic units. To steadily reduce the difficulties, we need a concrete
baseline evaluation and optimization methods based on it. In this talk, I
present a framework for evaluating critical components of FTQC. Then, I
will explain recent our results to optimize the performance of FTQC.

050

CP-07-03

Quantum error correction by low-depth random
Clifford circuits
Yoshifumi Nakata
Yukawa Institute for Theoretical Physics, Kyoto University

Abstract
Quantum random encoding is a method of generating quantum error
correcting codes (QECCs) by random quantum circuits and is known tohave high performance of correcting various noises. While it was
originally proposed as a theoretical technique, recent developments,
both from theoretical and experimental approaches, have opened thepossibility of realizing it by near-term quantum devices. In this work, weshow that QECCs generated by one-dimensional log-depth random
Clifford circuits can be efficiently decoded and have high performanceagainst stochastic Pauli noise. More specifically, we construct a
maximally-likelihood decoder based on the tensor-network method,which works efficiently if the encoding circuit is at most log-depth. Using
the decoder, we numerically show that the performance of the code
almost matches that of fully random ones if the circuit is at least logdepth. The combination of efficient decoding and high performanceagainst stochastic Pauli noise show that such codes are good candidates
for near-term quantum memories.

051

CP-07-04

Faster emulation of noisy VQE
Tyson Ray Jones
University of Oxford

Abstract
Variational quantum eigensolving (VQE) is a much touted application ofnear-future quantum computers. It involves the minimisation of a highdimensional (but polynomially growing) cost function which is classicallyintractable to evaluate, but quantumly efficient to explore. Many
minimisation strategies have emerged in the literature, from simple
quantum gradient descent which involves evaluating cost gradients, toquantum natural gradient which involves the quantum geometric tensor.
Classical emulation of VQE is tantamount in its study, but the time toclassically compute the aforementioned variational quantities becomes
an unignorable bottleneck. Recent works have devised bespoke
simulation algorithms to overcome this hurdle in noise-free settings,
though they cannot capture realistic noisy behaviours of present day
devices. We here present novel algorithms for asymptotically fasterclassical simulation of quantum gradient descent and the quantum
natural gradient, where the latter is generalised for channels andreplaces the geometric tensor with an approximate Fisher information
matrix. Our work permits the exact numerical investigation ofsignificantly larger variational problems in noisy settings described byarbitrary Kraus channels, which can themselves be parameterised. These
schemes have been integrated into QuESTlink, a Mathematica simulatorof quantum computers.

052

CP-08-01

One hundred second bit-flip time in a twophoton dissipative oscillator
Zaki Leghtas
Mines ParisTech / Ecole Normale Supérieure

Abstract
Current implementations of quantum bits (qubits) continue to undergo
too many errors to be scaled into useful quantum machines. An emerging
strategy is to encode quantum information in the two meta-stable
pointer states of an oscillator exchanging pairs of photons with its
environment, a mechanism shown to provide stability without inducing
decoherence. Adding photons in these states increases their separation,and macroscopic bit-flip times are expected even for a handful ofphotons, a range suitable to implement a qubit. However, previous
experimental realizations have saturated in the millisecond range. In thiswork, we aim to maximize the bit-flip time in a two-photon dissipative
oscillator. To this end, we design a Josephson circuit in a regime thatcircumvents all suspected dynamical instabilities, and employ aminimally invasive fluorescence detection tool, at the cost of a twophoton exchange rate dominated by single-photon loss. We attain bit-fliptimes exceeding 100 seconds in between states containing about 40
photons. This experiment demonstrates that macroscopic bit-flip times
are attainable with mesoscopic photon numbers in a two-photon
dissipative oscillator. This lays a solid foundation from which the twophoton exchange rate can be gradually increased, thus gaining access tothe preparation and measurement of quantum superposition states, andpursuing the route towards a logical qubit with built-in bit-flip protection.

053

CP-08-02

Real-Time decoding with a distributed controlstack architecture for fault-tolerant quantum
computingFrancesco Battistel
Qblox

Abstract
Quantum error correction (QEC) will be fundamental to ensure fault
tolerance and achieve a quantum advantage. An essential element of
QEC is the decoder, which protects the logical information by using the
syndrome information to infer the most likely error pattern. The decoder
must be accurate but also real-time to keep the quick pace of the QEC
cycle (<1us for superconducting qubits). However, there are two major
problems to achieve such a speed: the decoding speed per se and thecommunication latency with the rest of the control stack. To address thecommunication-latency issue, we propose and implement a distributed
control-stack architecture where measurement outcomes and Pauliframe updates are shared within a few hundreds of nanoseconds. Thisarchitecture includes and interfaces to a specialized module for runninguser-defined decoding algorithms. We review the most advanced
proposals for decoding algorithms aimed at achieving real-time
execution, with a focus on the classical computational resources (FPGA,
ASIC) that are employed. This talk is aimed at researchers and experts
from the quantum error correction, computer science, classicalarchitectures and digital design communities.

054

CP-08-03

Tileable low-crosstalk 3D-integrated
superconducting circuits
Peter Leek
University of Oxford

Abstract
Superconducting circuits are a leading candidate for the realization ofpractically useful quantum computers, in particular for near-term
applications which may already be reached with circuits consisting of afew hundred qubits operated at high fidelity. Until recently, the topologyof superconducting circuits has typically been constrained to twodimensions, which becomes difficult to scale as the number of qubits
increases and signal wiring is needed for qubits in the middle of large
arrays. In this talk I will present our progress [1] on scaling up a novel
circuit architecture that builds on a tileable superconducting circuit unit
cell with coaxial symmetry and 3D-integrated off-chip wiring [2], which
provides a viable route to operating such large qubit arrays while
maintaining a clean microwave environment [3].
[1] Spring et al., Science Advances 8 (2022)[2] Rahamim et al., Applied Physics Letters 110, 222602 (2017)[3] Spring et al., Physical Review Applied 14, 024061 (2020)055

CP-09-01

Practical quantum computing
Mark W Johnson
D-Wave Systems Inc.

Abstract
Quantum annealing continues to show great promise for solving hard
optimization problems that occur across a wide range of businessapplications, though there is much still to learn about its ultimate
potential. D-Wave has developed and delivered five generations ofsuccessively more powerful, commercial annealing quantum computers.
With the significant technological progress that has accompanied thedevelopment of these systems, it is now possible to perform thequantum annealing algorithm far more quickly than the systemdecoherence time. This has opened the door to harnessing large scalecoherent dynamics in the study of quantum phase transitions, as well as
solving optimization problems. Here Iʼll review a recent example in the
study of quantum critical dynamics in a programmable spin glass
comprising 5000+ qubits. Insights from this work, as well as from yearsof experience working with customers on their important businessproblems, are driving development of D-Waveʼs next generation
annealing quantum computer: Advantage2. I will review these insights,
as well as plans for a our next generation quantum annealing and gatemodel quantum computers.

056

CP-09-02

Search for quantum applications and taking
POCs to production
Helmut Katzgraber
Quantum Solutions Lab, Amazon Web Services

Abstract
The Amazon Quantum Solutions Lab works closely with enterprisecustomers to identify use cases where quantum technologies might have
impact in the fault-tolerant future, but also to develop creative ways tosolve complex business challenges at scale today. In this presentation, I
will showcase selected customer use cases and discuss where and whenquantum machines can have an impact.

057

CP-09-03

Quantum annealer based on Kerr parametricoscillators
Tsuyoshi Yamamoto
NEC Corporation

Abstract
Josephson parametric oscillator is a superconducting driven oscillator, inwhich the reso-nance frequency is modulated at twice of it with amodulation amplitude larger than a threshold. The oscillation states of a
JPO composed of two different states with the same amplitude but
opposite phase (0pi or 1pi) can be used as two basis states of a qubit. In
this talk, I will show our study on the basic physical properties of a JPO
toward the realization of a quantum annealing machine. I will also
introduce our three-dimensional packaging technologies, which arenecessary for the large-scale integration in the future.

058CP-10-01

Bob’s sidekick (or how tripartite quantum
correlations satisfy a type of rigidity and how
this is useful for cryptography)
Anne Broadbent
University of Ottawa

Abstract
We present a variant of the two-prover interactive proof model, where
the interaction pattern is limited to a 3-messages: setup-broadcastresponse. By virtue of these limitations, classically, the model has thesame power as the single-prover model where 3 messages areexchanged. In stark contrast, the quantum version of this model (which
we call the ‘Bob’s sidekick’ model) gives rise to monogamy-ofentanglement’ (MoE) games, wherein the limitation on tri-partite
entanglement hampers the provers, as compared to the single-provercase. We show how this limitation can be exploited for cryptographic
purposes, for instance in “unclonable encryption” where the capacity ofan adversary to copy a ciphertext is limited; this is achieved using an MoE
game based on conjugate coding. What is more, we show the first rigidity
theorem for this MoE game, which means that producing optimal winningstatistics strongly constrains the quantum strategy of the provers. From
this rigidity result, we derive a weak string erasure protocol, which
implies bit commitment — in a model where classical bit commitment is
impossible.
Based on joint work with Eric Culf (arXiv:2111.08081) and Sébastien Lord
(arXiv:1903.00130).

059

CP-10-02

Abstracting quantum computation
Joe Fitzsimons
Horizon Quantum Computing

Abstract
Quantum computers have the potential to drastically outperformconventional computers for a variety of tasks, from simulating molecularinteractions to machine learning. However, our understanding of how toconstruct non-trivial quantum algorithms is still in its infancy and humanintuition is not well suited to finding ways to accomplish computationaltasks through quantum interference. As a result, reaching a future where
quantum computing is widely used requires not only overcoming thechallenges of building scalable quantum computers, but also finding new
ways to program these systems to tackle new and more complex
problems.
In this talk I will introduce some of the work we have been doing at
Horizon Quantum Computing to simplify the task of programming
quantum processors through increasing levels of abstraction, and discuss
progress towards our goal of compiling classical code to take advantageof quantum processors, through automated synthesis of quantum
algorithms.

060

CP-10-03

Quantum cryptography without one-way
functions
Tomoyuki Morimae
Kyoto University

Abstract
One-way functions are the most fundamental primitives in classicalcryptography. In this talk, I show that in quantum cryptography, one-way
functions are not necessarily the most fundamental ones. We constructcommitments and digital signature from pseudo-random quantum states
generators. Pseudo-random quantum states generators are shown toexist even if BQP=QMA, which means that pseudo-random quantum
states generators exist even if all post-quantum classical cryptographic
primitives (inluding post-quantum one-way functions) are broken. Our
result therefore means that several quantum cryptographic primitives
can be constructed without one-way functions. This is a joint work withTakashi Yamakawa (NTT). [Morimae and Yamakawa, CRYPTO2022]061

CP-11-01

From a grain of sand to a |quantum〉bit of
information
James ClarkeIntel Corporation

Abstract
A large scale quantum computer could change the world; calculations inminutes that would take the supercomputers thousands of years.
Applications such as cryptography, chemistry, finance, etc are the focus.
Today’s quantum processors are limited to 10’s of entangled quantum
bits. If you believe the hype, a commercially relevant system is justaround the corner that can outperform our largest supercomputers for
useful calculations. The reality, however, is that a commercially relevant
system is 10-15 years away.
At Intel, our approach is to rely on the continued evolution of Moore’s
Law to build qubit arrays with a high degree of process control. Here, we
present progress toward the realization of a 300mm Si/SiGe based spin
qubit device in a production environment. A spin qubit relies on the spinof a single electron in an external magnetic field to encode the two statesof the qubit, where spin up vs down represent 0 vs 1. Spin Qubits arecompelling as their appearance and fabrication is similar to conventional
CMOS transistors that drive the microelectronics industry. At the sametime, they are roughly one million time smaller than the superconducting
qubits that are being pursued by other companies.

062

CP-11-02

Integration of silicon spin qubits with buried
nanomagnet: a trial to design integration
structure with quantum device simulator
Shota Iizuka
National Institute of Advanced Industrial Science and Technology (AIST)

Abstract
Silicon spin qubit is a promising candidate as the building block for largescale quantum computers because of their compatibility withconventional LSI fabrication technology. In the actual device fabrication,
the device characteristics vary due to process variation, causing
unexpected performance degradation. For example, the qubit fidelity
degrades due to the quantum dot size variation. Therefore, toward largescale integration, it is essential to consider the integration structure
realizing high variation tolerance. The device simulation technology helps
the situation because we can test the variation tolerance quickly. In thistalk, I will discuss a case study, taking advantage of a house-madequantum device simulator, about the co-integration of the qubits andnanomagnets, proposing a high variation tolerant integration structure.
That is with buried nanomagnets, which enable qubit operation withhigh-speed and suppressed fidelity variation. The high-speed operation
results from closely placed nanomagnets near the qubits, enabling about
ten times faster operation than the conventional case. Also, the proposed
structure suppresses the fidelity variation due to process variation
thanks to the self-aligned fabrication process. This work demonstrates
that a device simulator is a powerful tool in the integration structure
design toward the practical realization of large-scale quantum
computers.

063

CP-12-01

Quantum simulations using phonons in trappedions
Kenji Toyoda
Center for Quantum Information and Quantum Biology, Osaka University

Abstract
Trapped ions enable the preparation of a reliable platform that can beused to quantum computation and quantum simulations. In addition toqubits comprising of internal states in ions, the quanta of the ion crystalʼsvibrational motion, or phonons, which offer higher information capacity
per physical degree of freedom than qubits, are considered to bealternative computational resources. Phonons in trapped ions can beused to certain applications, including the simulation of stronglyinteracting particles, quantum walks, and analog quantum computation
using bosonic degrees of freedom. In this talk, I review the application ofphonons in trapped ions to quantum simulations, and explain our recent
progress regarding the system of polaritons in the Jaynes-CummingsHubbard model and quantum walks.

064

CP-12-02

Quantum simulation for quantum many-bodysystems: variational quantum algorithms andbeyondSeiji Yunoki
RIKEN

Abstract
As R. Feynman was originally suggested in 1982, quantum many-bodysystems are the most promising application for quantum computing.
Considering noisy near-term quantum devices with a relatively small
number of qubits, one of the main focuses in the current quantum
simulation research is to identify what one can do with such noisy
quantum devices that is not too trivial but still interesting. In this talk, I
would like to present some of our recent attempts to simulate quantum
many-body systems based on a quantum variational approach andbeyond [1-5].
[1] “Symmetry-adapted variational quantum eigensolver”, K. Seki, T.
Shirakawa, and S. Yunoki, Phys. Rev. A 101, 052340/1-15 (2020).
[2] “Discretized quantum adiabatic process for free fermions andcomparison with the imaginary-time evolution”, T. Shirakawa, K. Seki,and S. Yunoki, Phys. Rev. Research 3, 013004/1-32 (2021).
[3] “Quantum power method by a superposition of time-evolved states”,
K. Seki and S. Yunoki, PRX Quantum 2, 010333/1-45 (2021).
[4] “Spatial, spin, and charge symmetry projections for a Fermi-Hubbard
model on a quantum computer”, K. Seki, and S. Yunoki, Phys. Rev. A 105,
032419/1-34 (2022).
[5] “Parametrized quantum circuit for weight-adjustable quantum loopgas”, R.-Y. Sun, T. Shirakawa, and S. Yunoki, arXiv:2210.14662.

065

CP-13-01

Quantum information processing with trappedions
Jonathan Paul HomeETH Zürich

Abstract
Trapped-ions are among the leading systems for quantum computing,offering the highest accuracy gate operations and long coherence times.
Nevertheless, along with all candidate technologies, they face theconsiderable scaling challenge of transitioning from systems of tens ofqubits to hundreds of thousands. I will describe the state of the field, inthe context of experiments performed in our group which focus onchallenges and possible solutions for scaling up. This includes newtechnological approaches to delivering light as well as novel methods oftrapping or encoding information.

066

CP-14-01

Building small, fast and hot hole spin qubits in
Si and Ge
Dominik Max Zumbuhl
University of Basel

Abstract
Quantum computers hold the potential to execute complex tasks
exponentially faster than classical computers. Hole spins in Ge/Si core/shell nanowires experience an exceptionally strong yet electricallytunable spin-orbit interaction, allowing unprecedented qubit control. We
can tune the Rabi frequency with gate voltages, going from a fast
manipulation to an idle mode, demonstrating a spin–orbit switch. We
show spin-flip times as short as ~1 ns, approach the strong driving
regime, due to a very strong spin-orbit interaction, with spin-orbit length
down to a few nm. This qubit can also operate at 1.5 K, where we are also
implementing an exchange based CROT 2Q gate.
One of the greatest challenges in quantum computing is achieving
scalability, solved with the fin field-effect transistor (FinFET) in classicalcomputing, integrating billions of transistors on silicon chips. Here, weshow that silicon FinFETs can host hole spin qubits operating above 4 K,
potentially allowing in-situ integration of qubit control electronics. We
achieve fast all-electrical control and single-qubit gate fidelities at thefault-tolerance threshold. Further, we demonstrate a CROT 2Q gate with
spin-orbit induced anisotropic exchange interaction, opening the door tohigh fidelity and fast 2Q gates.

067

CP-15-01

Algorithms and Architectures for the ‘Late NISQ’
and ‘Early Fault-Tolerant’ Eras
Simon Benjamin
University of Oxford

Abstract
I will discuss the opportunities for quantum advantage in the anticipatederas of ‘late NISQ’ (meaning, many physical qubits) and the early faulttolerant (meaning, a modest number of encoded qubits). In both these
periods, we will need to closely match algorithms to architectures inorder to have good prospects for quantum advantage. The specificthemes I will touch on include the practicality of error mitigation anderror correction (e.g. [1] and [2]), leading into architectural concepts suchas multicore and looped-pipeline processors [3,4]. I will note thatcompilation (also known as circuit synthesis) is vital to extract maximum
value, and can be done either classically or using a quantum devices [5].
Finally I will describe an approach to chemistry simulation that iscompatible with the Early FT Era, with the prospect of handlingclassically-intractable dynamics using only hundreds of logical qubits [6].
[1] arXiv:2210.00921[2] arXiv:2211.08468[3] Phys. Rev. Applied 18, 044064 (2022)[4] arXiv:2203.13123[5] arXiv:2206.11245 and arXiv:2206.11246;[6] arXiv:2202.05864

068

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TracksTracksPL

CP

Plenar y Sessions

Quantum Computing Track

Contents / Topics

Contents / Topics

Welcome from Organizing Committee and Hosts,
Plenary Talks, Keynote

Quantum Computing architecture, Quantum
computers with Atoms and Ions, Photonic Quantum
Computers, Fault Tolerant Quantum Computing,
Quantum Algorithms for Chemistry, NISQ
Algorithms, Young PIs Session, Superconducing
Quantum Computing, Quantum Annealing,
Verifiable Quantum Computing, Semiconductor
Quantum Computers, Quantum Simulations

TracksTracksCC

SE

Quantum Cr yptography &Communication Track

Quantum Sensing Track

Contents / Topics

Contents / Topics

Quantum Internet, Young Researcher Panel Session,
Quantum Cryptography

Q-sensors for Life Science, NV Center and Applications
for Life Sciences, Solid-State Quantum Sensors, 5th
IFQMS Short Presentation Session for Young
Scientists, Solid-State Quantum Sensors, Q-sensors
for Life Science, NV Center and Applications for Life
Sciences, Atom Interferometer, Atom/Ion Clocks *29th
Nov Sessions are a joint-program with The 5th IFQMS(The 5th International Forum on Quantum Metrology
and Sensing).

069

CC-01-01

Solid-state quantum emitters for quantum
networking
Elizabeth Goldschmidt
University of Illinois Urbana-Champaign

Abstract
Optically active and highly coherent emitters in solids are a promising
platform for a wide variety of quantum information applications,particularly quantum memory and other quantum networking tasks.
Rare-earth atoms, in addition to having record long coherence times,
have the added benefit that they can be hosted in a wide range of solidstate materials. We can thus target particular materials (and choose
particular rare-earth species and isotopes) that enable certain
application-specific functionalities. I will discuss several ongoing projects
with rare-earth atoms in different host materials and configurations. This
includes investigations of inhomogeneous broadening in rare-earth
ensembles and our efforts to identify and grow new materials with rareearth atoms at stoichiometric concentrations in order to reduce thedisorder-induced inhomogeneous broadening. I will also discuss ourwork on photonic integration of rare-earth emitters, namely developing
thulium doped thin-film lithium niobate as a platform for quantum
memory.

070

CC-01-02

Generation and manipulation of photonic
quantum states for quantum network
Takashi Yamamoto
Graduate school of Engineering Science / Center for quantum information and quantum biology, Osaka
University

Abstract
Quantum network among multiple quantum devices and/or users is oneof the important issues for realizing long-distance quantum
communication, large-scale quantum computer and quantum sensing.
Multimode quantum states and quantum frequency conversion (QFC)
play an important role for this purpose. QFC translates the frequency ofphotons entangled with quantum devices while retaining its quantum
properties for various applications. One of the examples for useful QFC is
to link the quantum devices to the telecom fiber network. On the other
hand, multimode quantum states are suitable for multi-usercommunications and the enhancement of communication capacity. In
this talk, I report an efficient and wide-range generation of the quantum
frequency comb based on a quadratic nonlinear optical waveguide insidea cavity, which can be useful for generating multi-dimensional photonic
quantum states and frequency multiplexed photon pairs. Using the samedevice, we also show an efficient QFC and a frequency manipulation
method.

071

CC-01-03

Quantum communication in network channels
and multipartite entanglement distribution
Masahiro Takeoka
Keio University

Abstract
Efficient entanglement and secret-key distribution over the network
channels is necessary to build a global quantum internet. One of the key
technologies for this is quantum repeater. It is important to clarify what is
the fundamental performance limit without quantum repeaters and how
to overcome it by quantum repeaters, hopefully with relatively simpler
technologies. These are intensely investigated for a point-to-point
channel with two users but still many things are missing for network
channels, in particular, for multipartite entanglement distribution. Here
we discuss two examples: 1) fundamental limit of bipartite entanglement
and key distribution and a novel multi-party quantum key distribution
protocol in a quantum broadcast channel, and 2) quantum repeater-like
operations for multipartite entanglement distribution in a star-type
network channel.

072

CC-01-04

Quantum repeater for continuous-variableentanglement distribution
Josephine Dias
Okinawa Institute of Science and Techology

Abstract
Quantum communication enables various technological possibilities thatare hard or impossible with classical communication. These include
secure distribution of keys, transfer of quantum information anddistributed quantum computation and sensing. However, utilizing thesetechnologies over long distances remains challenging due to fiber loss or
free-space attenuation. Quantum repeaters have been proposed as away of extending the reach of quantum communication. First- generation
approaches use entanglement swapping to connect entangled links
along a long-distance channel. While repeaters for discrete variable
encodings of quantum information have existed for some time, several
approaches for continuous variable encoding quantum repeaters havebeen proposed within the last five years. In this talk, I will introduce ourapproach to a quantum repeater for continuous variables using
homodyne detection with post-selection for entanglement swapping andnoiseless linear amplification for entanglement distillation. I will alsopresent a method of using a discrete variable repeater protocol to
distribute continuous variable states and utilize it to compare the rates ofcontinuous variable entanglement distribution between first generation
continuous and discrete variable quantum repeaters. Such a comparison
allows us to begin to benchmark the two quite different approaches.

073

CC-01-05

Entanglement distribution for QKD overtelecom fiber
Christian Kurtsiefer
Centre for Quantum Technologies

Abstract
A key primitive in quantum networks is entanglement distribution, andbridging large distances usually requires photons at the transparency
windows of telecom fibers. Moderate photon pair rates fromconventional down conversion sources limit fiber-based entanglement
distribution. A bright non-degenerate photon pair source, designed forhigh idler photon detection efficiency on single-photon avalanche
photodiodes and low signal photon dispersion in optical fiber, enableshigh pair rates even after propagating through 50km standard
telecommunication fiber. We present application of such a source forquantum key distribution using a BBM92 protocol.

074CC-03-02

Quantum communication at Airbus
Matthieu Dollon
AirbusAbstract
Quantum Communication addresses Quantum Cryptography and
Quantum Internet: 2 domains of high interest for Airbus, with a lot ofsynergies with classical optical communication systems (Airbus is aworldwide leader).
Airbus leads all the preparatory activities under the umbrella of theEuroQCI flagship of the European Commission, with the partnership of
ESA:-Qosac, large system study in 2020
-QUBITS, phase A for the space component in 2021-2022-Oqtavo, preliminary system definition of the overall system focuses on
the terrestrial network
Airbus is preparing to be the prime system integrator of the futuresatellite, user segment and ground segment, for both the QKD systemand the Quantum Internet systems. The technical solution are alreadyunder preparation, and are based on the large heritage of Airbus on
optical communication and optical observation satellites. These
solutions offer high throughput systems that are necessary to build aquantum communication systems, and achievable now thanks to past
heritage.
For the terrestrial network, the role of Airbus is to lead the design andimplementation of the SDN and associated control and management
plan, in order to offer a consistent secured system in synergy with the
future USC, the European Connectivity Constellation.

075

CC-03-03

Information theoretically secure data utilization
using “Quantum Secure Cloud”
Mikio Fujiwara
NICT

Abstract
We have been developing a system that implements a secret sharing
protocol on a QKD network to enable secure transmission, storage, andsecondary use of data. We have developed an XOR based high-speed
secret sharing and high-speed OTP encryption/decryption system for
distributed data backup. The throughputs of these systems are 700 Mbps
and over 2 Gbps, respectively. We named the system Quantum Secure
Cloud. We named the system “Quantum Secure Cloud” and have been
conducting POC in various fields. This system not only transmits andstores genome analysis data, which require long-term confidentiality, but
is also expanding its functions as a platform that enables secure
utilization of data. For the secondary use of secure data, we havedeveloped a system in the Quantum Secure Cloud that uses a securecomputation system based on the assumption of a trusted server, wheredata is restored only during computation and encrypted during input/
output. The system also has a filtering function to prevent unnecessary
leakage of personal information. To our knowledge, this is the first in theworld to analyze whole genome data in an information-theoreticallysecure manner. In this presentation, we will explain the details of thesystem.

076

CC-03-04

Field trials and recent activities of QKD
research in Toshiba corporation
Mamiko Kujiraoka
Toshiba Corporation, Corporate Research & Development Center

Abstract
Quantum key distribution (QKD) provides a means for exchanging
cryptographic keys, the security of which makes no assumptions about
an adversaryʼs computing power or technological capability. Toshiba
corporation is leading QKD technology in research, field trials, andstandardization activities. This talk presents mainly QKD field trials in
medical field: a real-time transmission of genome analysis data, atransfer of online expert panel data, and a backup of large-scale genome
analysis data to multiple sites in cooperation with Tohoku University
Tohoku Medical Megabank Organization (ToMMo), Tohoku University
Hospital, and the National Institute of Information and Communications
Technology (NICT). We also overview recent activities of QKD research in
Toshiba corporation.

077

CC-03-05

Advancements in space quantum
communications
Paolo Villoresi
University of Padova

Abstract
The development of quantum technologies is in a phase of consolidation.
With regard to quantum communications and, the development of fiber
demonstrations has in fact been underway for over two decades, while
the results along the space channels have shown the feasibility in thisdomain for over five years. The analysis of chronological developments
and applications will be presented together with recent experimental
results.

078

CC-03-06

Entanglement distribution and next challenges
Alexander Ling
Centre for Quantum Technologies, National University of Singapore

Abstract
In my talk, I will give an overview of entanglement distribution work thathas been performed in Singapore, and our plans for the next steps. I will
discuss a recent result where we look at the overall system performancefor generation and detection of entangled photons in the NIR regime, anddiscuss how it can enable small scale local networks using
telecommunication fiber.

079

CC-03-07

Satellite-based QKD for global quantum
cryptographic network construction
Saori Kijima Yokote
Space & Defense Business Division Space&Satellite Business Group Space Business Unit SKY Perfect JSAT
Corporation

Abstract
In recent years, the development of quantum key distribution (QKD) andcryptographic techniques have been promoted worldwide. Also in Japan,
various QKD research and development projects are being conducted,
including a publicly solicited R&D project by the Ministry of Internal
Affairs and Communications (MIC).
SKY Perfect JSAT Corporation (SJC), Asiaʼs largest satellite operator, hasbeen selected as the representative company of the consortium for“Research and Development of Satellite Onboard QKD and Cryptography
Technologies for the Construction of Global Quantum Cryptography
Network” (MIC public offering) publicly solicited by MIC in 2021.
The consortium to execute the project which consists of National
Institute of Information and Communications Technology (NICT), NEC
Corporation, TOSHIBA CORPORATION, and SJC, and they have been
contributing on Japanese QKD and Cryptographic Technology
development.
This presentation describes the latest QKD R&D and commercialization
trends in several countries around the world, the concepts and therequirements of MIC public offering, and the role of the consortium in the
project and its progress so far. In addition, this presentation describes
about the prospects for future business development of SJC, associatedwith the satellite-based QKD.

080

CC-04-01

Resource efficient fault-tolerant one-way
quantum repeater with code concatenation
Johannes Borregaard
QuTech, Delft University of Technology

Abstract
One-way quantum repeaters where loss and operational errors arecounteracted by quantum error correcting codes can ensure fast andreliable qubit transmissions in quantum networks. It is crucial that therequirements of such repeaters such as the number of spin-photon
interfaces per repeater station, the gate error rates, and loss rates withina repeater node are reduced to allow for near-future implementations. In
this talk, I will discuss a recent proposal of a one-way quantum repeaterthat targets the general asymmetry between loss- and operational error
rates in a communication channel in a resource efficient manner usingcode concatenation. Specifically, we consider a tree-cluster code as anouter loss-tolerant code concatenated with an inner 5-qubit code forprotection against Pauli errors. Adopting flag based stabilizer
measurements, we show that intercontinental distances of up to 10,000
km can be bridged with a minimal resource overhead by interspersing
repeater stations that operates differently at the two codes. Our work
demonstrates how tailored error correcting codes can significantly lower
the experimental requirements for long-distance quantum
communication.

081

CC-04-02

Entanglement of trapped-ion qubits separated
by 230 m
Tracy Northup
University of Innsbruck

Abstract
Entanglement-based quantum networks hold out the promise of newcapabilities for secure communication, distributed quantum computing,and interconnected quantum sensors. However, only a handful ofelementary quantum networks have been realized to date. I will present
recent results from our prototype network, in which two calcium ions areentangled with one another over a distance of 230 m, via a 510(2) m
optical fiber channel linking two buildings. The ion-ion entanglement isbased on ion-photon entanglement mediated by coherent Ramanprocesses in optical cavities. I will discuss the advantages of trapped ionsfor quantum networks and the role that cavities play as quantum
interfaces between light and matter. After examining the key metrics offidelity and success probability, we will consider how this work may be
extended in the future to long-distance networks of entangled quantum
processors.

082

CC-04-03

From quantum repeater networks to thequantum internet
Hideo Kosaka
Quantum Information Research Center at Yokohama National University

Abstract
Our challenges of developing quantum repeaters using diamonds andquantum interfaces for superconducting qubits will be presented forbuilding quantum repeater networks and quantum computer networks
for the quantum Internet.

083

CC-04-04

Quantum repeaters: Analytical models andoptimized protocols
Peter van Loock
University of Mainz

Abstract
We give an overview of our effortsto model fiber-based, memory-based
quantum repeaters for long-range quantum key distribution or moregenerala quantum network applications.
Under given experimental assumptions such as the possibility ofprobabilistic or deterministic entanglement swapping we calculate andoptimize the final (secret key) rates for medium-size repeaters including
the most important experimental parameters. We also briefly discusspossible variations such as memory-free approaches based on bosonicquantum error correction codes.

084

CC-05-05

Telcoʼs experience and perspective on Quantum
Cryptography
Hans Hyungsoo KIM
KT corp.

Abstract
KT corp. has experienced lots of field trials which were derived from selfdeveloped Quantum Cryptography technologies. And also KTʼs QKDbased leased line service was commercialized. In this presentation, thoseexperiences and relative lessons learned are introduced. Based on
Quantum technologies originated from Quantum Cryptography, KTʼsperspective towards Quantum Era is focusing on Quantum Internet.

085

CC-05-06

The UK quantum communications hub
Timothy Paul Spiller
University of York UK

Abstract
For context, Iʼll give a short overview of the UK National Quantum
Technologies Programme (NQTP) and the position of the Quantum
Communications Hub within the NQTP. Iʼll summarise the successful
outcomes of Phase 1 (2014-19) of our Hub work and the expanded
portfolio of research and development that we are pursuing during Phase
2 (2019-2024). Iʼll feature a few examples of this work in a little moredetail.

086

CC-05-07

Quantum communication and cryptography inFranceEleni Diamanti
CNRS and Sorbonne University

Abstract
We discuss recent progress and current challenges and priorities in thedevelopment of quantum communication and cryptography
technologies and infrastructures in the context of the French quantum
national initiative. These technologies span all development stages andcorresponding applications of quantum networks, from quantum key
distribution to advanced functionalities based on entanglement
distribution and quantum memories, and are situated in the generallandscape of European and global developments in the field.

087

CC-05-08

DemoQuanDT: The quantum communication
testbed for Germany
Oleg Nikiforov
Deutsche Telekom Technik GmbH

Abstract
The national research project DemoQuanDT aims to demonstrate thefirst advanced quantum communication link in Germany. It will connect
Bonn, the former capital, to Berlin, today’s capital, with intermediate
trusted nodes in several relevant locations. The goal is to implement a
carrier-grade solution with real, hardened QKD devices, key storages andstate-of-the-art symmetric encryptors and decryptors. These will be
subjected to functional and security tests. Specific performance
evaluations and vendor benchmarks will be conducted. DemoQuanDT is
DT’s most relevant QKD project and is intended to verify a future ‘highlysecure transport service’ for critical communication in Germany.
DemoQuanDT is carried out in collaboration with ADVA Optical
Networking, Rohde & Schwarz Cybersecurity, KEEQuant and universities
and receives funding from the Federal Ministry for Research and
Education.

088

A bst r act

TracksTracksPL

CP

Plenar y Sessions

Quantum Computing Track

Contents / Topics

Contents / Topics

Welcome from Organizing Committee and Hosts,
Plenary Talks, Keynote

Quantum Computing architecture, Quantum
computers with Atoms and Ions, Photonic Quantum
Computers, Fault Tolerant Quantum Computing,
Quantum Algorithms for Chemistry, NISQ
Algorithms, Young PIs Session, Superconducing
Quantum Computing, Quantum Annealing,
Verifiable Quantum Computing, Semiconductor
Quantum Computers, Quantum Simulations

TracksTracksCC

SE

Quantum Cr yptography &Communication Track

Quantum Sensing Track

Contents / Topics

Contents / Topics

Quantum Internet, Young Researcher Panel Session,
Quantum Cryptography

Q-sensors for Life Science, NV Center and Applications
for Life Sciences, Solid-State Quantum Sensors, 5th
IFQMS Short Presentation Session for Young
Scientists, Solid-State Quantum Sensors, Q-sensors
for Life Science, NV Center and Applications for Life
Sciences, Atom Interferometer, Atom/Ion Clocks *29th
Nov Sessions are a joint-program with The 5th IFQMS(The 5th International Forum on Quantum Metrology
and Sensing).

089

SE-01-01

Dynamics and mechanism of dimer
dissociation of UVR8 photoreceptor
Dongping Zhong
The Ohio State University

Abstract
UVR8 (UV RESISTANCE LOCUS 8) proteins are a class of UV-B
photoreceptors in high plants. UVR8 is a homodimer that dissociates intomonomers upon UV-B irradiation (280 to 315 nm), which triggers various
protective mechanisms against UV damages. Uniquely, UVR8 does notcontain any external chromophores and utilizes the natural amino-acid
tryptophan (Trp) to perceive UV-B light. Each UVR8 monomer has 14
tryptophan residues. However, only the two Trp residues (W285 W233)
are critical to the light-induced dimer-to-monomer transformation. Here,
combining time-resolved spectroscopy, extensive site-directed
mutations and quantum calculations, we have revealed the entire
dynamics of UV perception to lead to monomerization, including a seriesof critical dynamic processes of a striking energy-flow network, exciton
charge separation and recombination, charge neutralization, salt-bridge
unzipping, and protein solvation, providing a complete molecular pictureof the initial biological function.

090

SE-01-02

Photoactivation of rhodopsins
Hideki Kandori
Nagoya Institute of Technology

Abstract
Rhodopsins are photoreceptive membrane proteins that bind retinal
chromophore. In animals, rhodopsins work for vision, while microbial
rhodopsins work for various functions such as light-driven ion-pumps,
light-gated ion-channels, light sensors and light-activated enzymes.
Optogenetics, which revolutionized brain sciences, started using
channelrhodopsin as a tool.
Color tuning mechanism in our vision is a key question in the field, as we
can discriminate various colors using three proteins (blue, green, and red
absorbing rhodopsins) with a common chromophore, 11-cis retinal.
There have been little structural studies, while our vibrational
spectroscopy revealed unique structural features of our color visualrhodopsins.
Light causes specific retinal isomerization; 11-cis to all-trans in animalrhodopsins, and all-trans to 13-cis in microbial rhodopsins. An important
aspect of photoisomerization in rhodopsins is that the shape-changing
reaction occurs even at 77 K, where protein environment cannot move by
freezing. Therefore, specific isomerization mechanism attracts many
researchers.
In my talk, I will introduce recent topics of animal and microbial
rhodopsins, including color tuning mechanism of our color-sensitive
rhodopsins, and unusual photoisomerization pathway and temperatureeffect found in new microbial rhodopsins.

091

SE-01-03

How can we measure the quality of
consciousness?
Makiko Yamada
QST

Abstract
Many of the major neuroscience studies to date on the quality of
consciousness, aka qualia, have utilized visual illusions. For example, inpolysemic figures such as Rubin’s vase or binocular rivalry, only one of
the two visual images rises to consciousness and switches at regularintervals. By exploiting such illusions, brain activity that changes incorrelation with the content of consciousness has been identified, eventhough the external stimuli are constant. However, most previous studies
have trivialized the quality of consciousness into a binary question ofwhether a particular visual image was seen or not, and examined thecorresponding brain activity, and have not been able to capture qualia
themselves (e.g., subjectively perceived redness of an apple) in terms ofbrain activity.
In my talk, I will present two of our new approaches to the quality of
consciousness, which has been difficult to define. One is to apply the
Yoneda Lemma to characterize qualia in relation to their surroundings
and identify qualia structure from brain activity patterns. The otherapplies the idea of “quantum cognition” to test whether the experienceof consciousness is determined by measurement by examining violationsof Bell’s inequality.

092

SE-02-01

Quantum sensing and imaging with diamond
spins
Ania Claire Bleszynski Jayich
UC Santa Barbara

Abstract
Solid state spin qubits, in particular the nitrogen vacancy (NV) center indiamond, offer a path towards truly nanoscale imaging of condensed
matter and biological systems with sensitivity to single nuclear spins.
Here I discuss our NV-based magnetic imaging experiments as applied tocondensed matter systems, where we have imaged current flow patterns
in graphene in order to reveal the transition from ohmic to electroncollision-dominated flow regimes. A grand challenge to improving the
spatial resolution and magnetic sensitivity of the NV is mitigating surfaceinduced quantum decoherence, which I will discuss in the second part ofthis talk. Decoherence at interfaces is a universal problem that affects
many quantum technologies, but the microscopic origins are as yet
unclear. Our studies guide the ongoing development of quantum control
and materials control, pushing towards the ultimate goal of NV-based
single nuclear spin imaging.

093

SE-02-02

Hybrid diamond-doped optical fibres for remotemagnetometry applications
Brant Gibson
RMIT University

Abstract
The ability to persistently monitor weak magnetic fields is a key objective
in long-term surveillance. One approach to meeting this goal is thedevelopment of optical fibre-based magnetometers capable of remote
operation. Diamond containing the negatively-charged nitrogen vacancy
colour centre (NV) is emerging as an important system for the sensing ofvarious physical parameters including magnetic field and temperature.
Many existing diamond NV magnetometers require complex microscopes
to monitor the fluorescence signal, which can restrict NV to laboratory
settings. Here I will discuss the fabrication and characterization of an
intrinsically magneto-sensitive optical fibre with potential applications as
a high-efficiency remote magnetic sensing platform. The hybrid fibre
allows for optical interrogation of NV-spin states via bound modes in ahighly-stable waveguide structure. Our results open the possibility ofrobust, field-deployable fibre optical magnetometry for a broad range ofquantum sensing applications.

094

SE-02-03

Quantum sensing by NV centers in diamondsemiconductor
Norikazu Mizuochi
Kyoto University

Abstract
The NV center in diamond has been attracting attention from theviewpoint of the application of ultrasensitive sensors and quantum
information devices. In the NV center, the spin of the single NV center canbe observed at room temperature despite the spin in the solid. In
addition, it has the longest Hahn-echo electron spin coherence time (2.4ms) and imhomogeneous electron spin dephasing time (1.5 ms) amongroom-temperature solid state systems [1]. We consider that theelongation of coherence times in n-type semiconductor diamond paves
the way to the development and application of diamond-based
quantum-information, sensing, and spintronics devices.
The dynamic range is also important from the viewpoint of theapplication. Conventional sensors have difficulty simultaneously
achieving high sensitivity and a large range. On the other hand, we havedemonstrated to widen the dynamic range while maintaining sensitivity,
which can be applied to the NV center [2]. In addition, we will also show
our recent research on low-frequency quantum sensing.
We thank supports from MEXT-QLEAP (No. JPMXS0118067395,
JPMXS0120330644), JSPS KAKENHI (No. 21H04653).
[1] E. D. Herbschleb, et al., Nature Communications, 10, 3766 (2019).
[2] E. D. Herbschleb et al., Nature Communications, 12, 306 (2021).

095

SE-04-01

Controlling and exploiting defects in diamondfor Quantum Technologies
Mark Newton
University of Warwick

Abstract
Point defects in diamond have great potential for use in a range ofquantum technologies. For example as single photon sources andquantum bits that can be exploited in quantum information processing
and as the heart of sensors that will transform the way we do analyticalscience and medical imaging. The negatively charged nitrogen-vacancy
centre is an amazing defect in diamond that possesses properties highly
suited to many of these applications. However, it does have somechallenging weaknesses and full exploitation of the optical and spin
properties of this and other defects necessitates that we control theirposition, orientation and environment to optimise all of the desirable
properties simultaneously, especially near the surface of the diamond. I
will review our understanding of the production of intrinsic defects andpresent new data on the creation of defect complexes by doping,electron irradiation, short pulse laser irradiation, ion implantation andannealing. The success and failure of different combinations ofprocessing steps to control and optimise the local defect environment
will be discussed and the ongoing search for alternate colour centres withcomparable spin properties and superior optical properties will be
reviewed.

096

SE-04-02

Methods for deterministic production of colour
centres in diamond
Jan Meijer
Leipzig

Abstract
The NV centres in diamond are currently the only solid-state qubits thatallow miniaturised construction and guarantee operation at room
temperature. This is the only way to build processors for broadcommercial use. While the methods for controlling and reading out thesecentres have been known and tested for years, the production of thecentres has been the main unsolved technological challenge.
In order to achieve successful coupling of the NV centres, a very small
spacing window has to be considered. When addressing the NVs, theirdefined alignment in the crystal is also necessary. Many NVs can only beread out electrically.
Here, many material-scientific but also technical boundary conditions
have to be taken into account. The lecture shows new approaches toovercome this challenge. The solutions could also be of importance forother applications.

097

SE-04-03

Synthesis of single crystal diamond with colour
centres for quantum applications
Alexandre TALLAIRE
Institut de Recherche de Chimie Paris CNRS

Abstract
The negatively charged nitrogen-vacancy centre (NV) in diamond is apoint-like defect that has focused a lot of attention in the past few years
due to its potential in quantum applications, especially for sensing. It has
bright single photon emission and the electronic spin state of this defectcan be optically read-out and manipulated leading to exceptionally longcoherence time even at room temperature. Harnessing the outstanding
properties of NVs mainly relies on the progresses in the synthesis of highquality and purity diamond material using the chemical vapour
deposition technique (CVD). Individual or ensembles of NV centres can becreated in an environment with low nuclear spin bath using 12C-enriched
CVD diamond plates. In addition, NV density can be controlled over awide range of concentration, from a few ppb to a few ppm with specificspatial localization. An additional advantage includes the ability topromote one orientation among the 4 possible axes of the NV dipole bygrowing on specific orientations such as (111) and (113). These
requirements are however very challenging and are setting an increasingpressure to the diamond synthesis capabilities by CVD. In this talk I will
describe the efforts dedicated to the growth of nitrogen-doped CVD
diamond single crystals by CVD that have allowed optimizing the material
for quantum sensing applications.

098

SE-04-04

Introduction to quantum brilliance and its R&D
programs
Marcus Doherty
Quantum Brilliance Pty Ltd

Abstract
Quantum Brilliance is an Australian-German company developing roomtemperature quantum computers based upon diamond. Quantum
Brilliance is distinguished by its distinct and complementary vision of‘quantum accelerators’. Being quantum computers that are the same size
as today’s GPUs and CPUs, which are deeply integrated with classicalcomputers to accelerate applications across the spectrum of edge
computing (e.g. in satellites and autonomous vehicles) to centralised
supercomputing (e.g. as massively parallelised clusters). Indeed,
Quantum Brilliance has already constructed a prototype quantum
computer and integrated it into the Pawsey Supercomputing Centre inAustralia. Alongside this premier hardware product, Quantum Brillianceis working with partners (e.g. NVIDIA) to drive the development of thesoftware frameworks, languages and libraries required to employ
quantum computers as accelerators in hybrid computing.
In this talk, I will briefly introduce Quantum Brilliance before outlining its
research and development programs.

099

SE-05-01

Hyperpolarized solution-state NMR
spectroscopy via quantum resources
Ilai Schwartz
NVision Imaging Technologies GmbH

Abstract
Nuclear spin hyperpolarization provides a promising route to overcome
the challenges imposed by the limited sensitivity of NMR spectroscopy.
The current leading approach for hyperpolarizing nuclear spins,
dissolution DNP, requires deep cryogenic temperatures (~1K) and longpolarization buildup times (~1 hour) thus limiting the applicability ofhyperpolarization. In this talk I will present our alternative method forenabling nuclear hyperpolarization of a wide range of molecules at room
temperature and under a minute utilizing quantum resources - opticallypolarizable electron spins in crystals and singlet states in gaseoushydrogen molecules.
We demonstrate that utilizing the quantum resource a molecule of choice
can be sufficiently polarized to serve as a “polarization source”. Mixing ahigh enough concentration of the polarization source molecule into thesolution enables polarization of an extremely wide range of analytes via
the intermolecular nuclear Overhauser effect (NOE), and achieves
enhancements up to 2600 in benchtop NMR spectrometers.
I will discuss the recent advances achieved by using various polarization
sources, the ongoing development for making the system widely
accessible to the NMR community and potential “killer applications” of
the technology.

100SE-05-02

Dissolution dynamic nuclear polarization
Jan Ardenkjaer-Larsen
Technical University of Denmark

Abstract
Hyperpolarized Magnetic Resonance is a new medical imaging modalitythat offers exceptional possibilities to follow changes in metabolism. The
method is enabled by a more than 10,000 fold enhancement of thenuclear magnetisation from metabolic contrast agents that probe central
metabolic pathways. The contrast agent is typically enriched in 13C andpolarized by dissolution Dynamic Nuclear Polarization (dDNP). The
contrast agent circulates via the vasculature to the tissue of interest,
where it is taken up by the tissue cells and metabolized into specificproducts. MR is unique in several ways: 1) it already provides anatomical
and morphological images with high resolution and contrast based on
the tissue water protons, 2) it is does not expose the patient to any
ionizing radiation, and 3) it is a spectroscopic method that allows
quantification of the individual metabolites. The first tracer in clinicaldevelopment is 13C-pyruvate. Pyruvate is at a pivotal point in glycolysis
and allows us to directly probe the Warburg effect through the elevatedlactate-to-pyruvate ratio. The hope is that more accurate diagnosis andstaging can be made, and that the method will provide an early read-outof response to treatment. The first clinical studies have been performed
with encouraging results, e.g. aggressiveness staging of prostate cancer.

101

SE-06-02

Toward rotation sensing using a trapped single
ionTakashi Mukaiyama
Osaka University

Abstract
Matter-wave interferometers typically exploit entanglement between theinternal state and the motional state of matter. The development of agyroscope using an ion trap is being pursued because of the highsensitivity to rotation and insensitivity to translational acceleration. Here
we aim to realize a rotation measurement using a trapped single ion
based on a matter-wave Sagnac interference by exciting the motion of
the ions to form a two-dimensional circular orbit. Although the matterwave interference of ions in multi-dimensional motion is essential for
gyroscopes using circular orbits, only one-dimensional interference wasrealized before our achievement. Our experiment has succeeded inobserving matter-wave interference of ions in three-dimensional motion
by exciting the motion of 171Yb+ ions using a mode-locked laser. To
realize a large interferometric area, we have developed a technique tosignificantly increase the ion orbital area by moving the ion trap center ina short time scale. We have also constructed a whole experimental setup
on a rotatable optical table, such that we can rotate the entire systemwith an angular velocity up to 2 degrees per second.

102

SE-06-03

Enhanced quantum control for the next
generation of optical lattice clocks
Andrew Ludlow
National Institute of Standards and Technology

Abstract
Atomic clocks operating in the optical domain are now capable ofmeasuring time at up to eighteen digits of precision. With the level ofclock stability that has also been demonstrated in optical clocks basedon ultracold atoms in an optical lattice, a promising route to even higher
performance exists. Here we explore new techniques for enhanced
control of lattice-trapped atoms towards next-generation optical latticeclocks. First, we consider two novel laser cooling strategies that exploit
the high atom-laser coherence possible with divalent atomic structure.
The first is a pulsed cooling process that replaces two-photon Raman
cooling techniques with single-photon velocity-selection on the clocktransition. The second is an excited state Sisyphus cooling mechanismthat offers efficient three-dimensional cooling in a lattice. We
demonstrate sub-recoil cooling of ytterbium in both cases, which aid in
loading very shallow lattices to reduce lattice-induced light shifts. We
also demonstrate coherent delocalization of ytterbium throughcontrolled tunneling in a Wannier-Stark lattice, aimed at reducing atomic
interactions within the lattice. Finally, we discuss progress on thedevelopment of portable ytterbium lattice clocks for future
measurements beyond the lab.

103

SE-06-04

Quantum metrology and computing using
microscopically-controlled arrays of alkalineearths
Kaufman M Adam
JILA, University of Colorado Boulder, NIST

Abstract
Quantum science with neutral atoms has seen great advances in the past
two decades. Many of these advances follow from the development of
new techniques for cooling, trapping, and controlling atomic samples. As
one example, the technique of optical tweezer trapping of neutral atomarrays has been a powerful tool for quantum simulation and quantum
information, because it enables scalable control and detection ofindividual atoms with switchable interactions. In this talk, I will describe
ongoing work at JILA where we have explored a new type of atom - twoelectron atoms - for optical tweezer trapping and manipulation. Whilethe increased complexity of these atoms leads to challenges, they alsooffer new scientific opportunities by virtue of their rich internal degrees
of freedom. Accordingly, they have impacted multiple areas in quantum
science, ranging from quantum information processing to quantum
metrology, and intersections therein. I will report on my group’s progressin these areas.

104SE-07-01

Quantum sensors with matter waves
Philippe Bouyer
Univ. of Amsterdam - Technical University Eindhoven

Abstract
The past decades has seen dramatic progress in our ability to manipulate
and coherently control the motion of atoms. Although the duality
between wave and particle has been well tested since de Broglie
introduced the matter-wave analog of the optical wavelength in 1924,
manipulating atoms at a level of coherence allowing for precision
measurement has only become possible thanks with our ability to
produce atomic samples of few microdegrees above absolute zero. Since
the initial experiments many decades ago, the field of coherent atom
optics has grown in many directions. This progress has both fundamental
and applied significance. The exquisite control of matter waves offers theprospect of a new generation of force sensors of unprecedented
sensitivity and accuracy, from applications in navigation and geophysics,
to tests of general relativity or study of highly-entangled quantum states.
The spectacular sensitivity or matter-wave interferometers can be usedfor very precise measure- ments. It is for example possible to measure
the acceleration of gravity with an accuracy of 1 part per billion, therotation of the Earth with an accuracy better than 1 millidegree per hourand detect minute changes in gravity caused by mass displacements.
These devices are so precise that they are used today as reference forfundamental constants (mass, gravity), and are powerful candidates totest general relativity on ground, underground or in space. Projects are
currently ongoing to verify the universality of free fall or to detectgravitational waves in a frequency range yet unreachable with current
detectors.
Nevertheless the future of matter-wave inertial sensors goes far beyondlab-based inertial sen- sors. While these experiments are typically quite
large, require a dedicated laboratory, and are desi- gned tooperate wellonly in environments where the temperature, humidity, acoustic noise istightly constrained, many efforts have been put in designing compact,robust and mobile sensors. The development of this technology lead to a
new generation of atomic sensors that have been operated in airplanes[10] and in rockets, that are commercially available and could be the next
generation of navigation unit.
105

SE-07-02

Exploring quantum gases for terrestrial andspace-borne interferometry
Maria Ernst
Leibniz Universität Hannover

Abstract
Ultra-cold quantum gases promise to boost the sensitivity of inertial
matter-wave interferometers, open the avenue to achieve higher
accuracies and allow to conceive new devices. Exploiting quantum gases
for high-precision interferometry places high demands on their control
and manipulation. The talk presents latest experiments to lower the
expansion energies of atomic ensembles and new possibilities arisingfrom twin-lattice interferometry. They are fascinating tools for groundand space-borne interferometry. Our research to advance the necessary
methods and achieve the targeted resolution benefits of various
platforms such as the very-long-baseline atom interferometer, theBremen drop tower, the Einstein elevator in Hannover, sounding rockets
and the international space station. The DLR-mission MAIUS-1
demonstrated Bose-Einstein condensation and performed firstinterferometry experiments during the space travel of a sounding rocket.
NASA’s Cold Atom Laboratory as well as the NASA-DLR funded BECCAL
facility continue this research in orbit on the ISS. These experiments
explore methods needed for high-precision interferometry as proposed
for Earth observation or fundamental physics experiments.
E.M.R. for the QUANTUS, MAIUS and BECCAL cooperation, dq-mat,terra-Q and quantum frontiers106SE-07-03

A highly charged ion based optical atomicclock
Lukas J. Spieβ
Physikalisch-Technische Bundesanstalt

Abstract
Optical atomic clocks are the most accurate devices ever built and areused as time standards as well as probes for fundamental physics. They
are usually based on transitions in neutral or singly charged atoms. The
large class of highly charged ions (HCI) remained so far unexplored. Thisis despite favourable properties of HCI, like a small sensitivity to external
fields and a high sensitivity to physics beyond the Standard Model. Overthe last decade several key hinderances were eliminated by sympathetic
cooling of HCI and interrogation using quantum logic spectroscopy.
Here, an optical clock based on the dipole-forbidden, optical transition in
Ar13+ is presented. A comprehensive analysis of the systematic shifts
shows a systematic uncertainty of 2*10^-17 with a clear path to below
10^-18. Clock comparison to the well-known octupole transition in singly
charged Yb yielded an absolute frequency eight orders of magnitude
more accurate than any previous value. The measured isotope shift (40Ar– 36Ar) is compared to high-precision calculations and reveals for the firsttime the quantum electrodynamic nuclear recoil in a many-electron
atom. The applied techniques are universal and open high precision
spectroscopy for a large variety of HCI.

107

SE-07-04

Robust Yb optical lattice clock for contributing
to International Atomic Time
Masami Yasuda
National Institute of Advanced Industrial Science and Technology (AIST), National Metrology Institute ofJapan (NMIJ)

Abstract
Recent rapid progress of the optical frequency standards motivates thediscussion on the redefinition of the SI second, which is presently definedby fixing the cesium microwave frequency value. The Consultative
Committee for Time and Frequency (CCTF) set mandatory conditions
which must be fulfilled before the redefinition. One of the most difficult
conditions is the regular contribution of the optical frequency standards
to the International Atomic Time (TAI), whose fulfilment index is less than
20 % in 2021. We will present our research activities on a robust
ytterbium (Yb) optical lattice clock aiming for the highest uptime forcontinuous operation. We implemented a laser frequency relocking
system fully utilizing our fiber-based optical frequency combs. A remotemonitoring system allows an unattained operation of the clock. Thanks
to these innovations, almost continuous operation of the clock with e.g.,
an uptime of 94.5 % for 30 days was made possible. After the verification
by CCTF Working Group on Primary and Secondary Frequency Standards,
we conduct on-time calibration of TAI 11 times in 2021 and 2022. The
most recent calibrations utilize an improved gravitational redshiftdetermined by a precise leveling and local gravity measurement by
Geospatial Information Authority of Japan.

108

A bst r act

TracksTracksPL

CP

Plenar y Sessions

Quantum Computing Track

Contents / Topics

Contents / Topics

Welcome from Organizing Committee and Hosts,
Plenary Talks, Keynote

Quantum Computing architecture, Quantum
computers with Atoms and Ions, Photonic Quantum
Computers, Fault Tolerant Quantum Computing,
Quantum Algorithms for Chemistry, NISQ
Algorithms, Young PIs Session, Superconducing
Quantum Computing, Quantum Annealing,
Verifiable Quantum Computing, Semiconductor
Quantum Computers, Quantum Simulations

TracksTracksCC

SE

Quantum Cr yptography &Communication Track

Quantum Sensing Track
Shor t Presentations by
Young Researcher sContents / Topics

Quantum Internet, Young Researcher Panel Session,
Quantum Cryptography

SE-03A , SE-03B

109

th
5 IFQMSThe 5th International Forumon Quantum Metrology and Sensing

PROCEEDINGS
Short Presentation Session for Young Scientists
Part 1: SE-03A

29 November, 2022
Online Conference (Zoom)
Joint Program Session with Quantum Innovation 2022

110

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

Quantum Sensing Track : Short Presentation Session for Young Scientists
SE-03A. Short Presentations 6HVVLRQIRU<RXQJ6FLHQWLVWV on SE-02, 04, 06, 07 Topics [5th IFQMS]*Note: Presentation order may change within the same group.
All the times in the program are Japan Standard time (GMT+9)
Nov 29 (Tue.)
13:10-14:30

13:10-14:30

Session / Presentation

Mentor / Presenter

ID

SE-03A-Į1
Chair

Ryota Katsumi

787

Co-chairNaota Sekiguchi

Tokyo Tech

Lock-In detected ramsey magnetometry with a bulk ensemble ofdiamond NV centers for high-sensitivity DC-field measurement

Sena Tsuchiya

Tokyo Tech

SE-03A-Į1-01

Towards measurement of magnetic field generated by the brain of aliving rat using N-V centers in diamond

Naota Sekiguchi

Tokyo Tech

SE-03A-Į1-02

Identification of current multipole sources frommagnetoencephalography data

Motofumi Fushimi

UTokyoSE-03A-Į1-03

Optimization of simultaneous measurement of magnetic field andtemperature measurement by silicon vacancy quantum sensor using
simultaneous resonanceTomoaki Tanaka

QST

SE-03A-Į1-04

Spin-dependent photocarrier generation dynamics in electricallydetected NV-based quantum sensor

Hiroki Morishita

Kyoto U

SE-03A-Į1-05

Towards nanoscale zero- to ultralow-field NMR

Till Lenz

JGU

SE-03A-Į1-06

Dipole-dipole interaction between NV- centers

Chikara Shinei

NIMS

SE-03A-Į1-07

Chair

Yuta Kainuma

Tokyo Tech

Co-chairNaoya Morioka

Kyoto U

Extension of dephasing time of ensemble NV centers with acontinuous-excitation protocol

Ikuya Fujisaki

Tokyo Tech

SE-03A-ȕ1-01

Wide temperature operation of diamond quantum sensor for electricvehicle battery monitoring

Keisuke Kubota

Tokyo Tech

SE-03A-ȕ1-02

A development of wearable magnetic shield for MEG

Soichiro Shido

UTokyoSE-03A-ȕ1-03

Attempts to generate entanglement state between dipolar coupled NV
centers created by molecular implantation

Kosuke Kimura

QST

SE-03A-ȕ1-04

Charge stability of shallow single NV centers in p-type diamond

Taisuke Kageura

A,67

SE-03A-ȕ1-05

Room-temperature electrical detection of nuclear spins in siliconcarbideNaoya Morioka

Kyoto U

SE-03A-ȕ1-06

JGU

SE-03A-ȕ1-07

SE-03A-ȕ1(Near) zero-field cross-relaxation features for ensembles of NV centers
2PNDU'KXQJHOin diamond
13:10-14:30

Affiliation

SE-03A-Ȗ1
Chair

Tomoya Sato

Tokyo Tech

Co-chair

Fumihiro China

NICT

Evaluation of a superconducting nanowire single photon detector for
mid-infrared wavelengths

Satoru Mima

NICT

SE-03A-Ȗ1-01*

Efficient superconducting nanostrip single-photon detectors for 2 �mwavelength

Fumihiro China

NICT

SE-03A-Ȗ1-02

Effect of pump laser linewidth on nonlinear quantum interferometricfringes

Jasleen Kaur

Kyoto U

SE-03A-Ȗ1-03

Highly efficient and ultra-broadband photon pair source using chirped
quasiphase matching slab waveguide matching slab waveguide

Bo CaoKyoto U

SE-03A-Ȗ1-04

Optical trapping and movement control of gold nanoparticles on an
optical nanofiber

Rui SunTohoku U

SE-03A-Ȗ1-05

Electromagnetic-field analysis of the plasmon-enhanced single photon
Yining Xuanemitters on an optical nanofiber

Tohoku U

SE-03A-Ȗ1-06

Ultrafast measurement of biphoton wave packets using optical Kerr
gating

UEC

SE-03A-Ȗ1-0

Takahisa Kuwana111

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)Nov 29 (Tue.)

Session / Presentation

Mentor / Presenter

Affiliation

ID

14:50-16:10 SE-03A-Į2
Chair

Naota Sekiguchi

Tokyo Tech

Co-chairRyota Katsumi

787

Growth of thick CVD diamond films containing aligned nitrogenvacancy centers for high-sensitivity quantum sensors

Takeyuki Tsuji

Tokyo Tech

SE-03A-Į2-01

Enhancement of fluorescence collection efficiency using angle-shaped
Yuta Shigenobu
diamonds for compact magnetic sensor

Tokyo Tech

SE-03A-Į2-02

Transfer-printing-based integration of SiN grating structure on diamond
Ryota Katsumi
toward highly sensitive quantum sensor

TUT

SE-03A-Į2-03

NVC-SPM system to inspect electric devices

Teruo Kohashi

HitachiSE-03A-Į2-04*

Enhancing sensitivity with entanglement in coupled nitrogen vacancy
centres

Ernst David Herbschleb

Kyoto U

SE-03A-Į2-05

Frequency-bin generation of entangled photons via quantum opticalsynthesis

Takeru Naito

UEC

SE-03A-Į2-06

Development of highly sensitive gravimeter based on atominterferometry using hybrid system for field applications

Takeshi Hojo

UEC

SE-03A-Į2-0

14:50-16:10 SE-03A-ȕ2
Chair

Naoya Morioka

Kyoto U

Co-chairYuta Kainuma

Tokyo Tech

Implementation of double quantum magnetometry to continuously
excited ramsey method

Yuta Araki

Tokyo Tech

SE-03A-ȕ2-01

Development of highly sensitive compact quantum sensor with NV
center in 12C-enriched CVD diamond for bio-medical and industrial
application

Yuta Kainuma

Tokyo Tech

SE-03A-ȕ2-02

Development of a nonmagnetic helical sensor drive multipoint
measuring mechanism for magnetocardiography in animals

Wenyu Shang

UTokyoSE-03A-ȕ2-03

Ensemble NV- center in diamond for quantum sensing created by highShuya Ishii
fluence electron beam irradiation

QST

SE-03A-ȕ2-04

Synthesis of n-type diamond using tert-butyl phosphine for highsensitivity of the NV sensor

Riku Kawase

Kyoto U

SE-03A-ȕ2-05

Decoherence phenomena in nitrogen-vacancy diamond

Aulden Jones*HRUJLD7HFK

SE-03A-ȕ2-06

Chair

Fumihiro China

NICT

Co-chairTomoya Sato

Tokyo Tech

Improvement in the long-term stability of the interferometer gyroscopeusing slow and continuous atomic beams

Naoki Nishimura

Tokyo Tech

SE-03A-Ȗ2-01

Bragg interferometer using slow and continuous atomic beam with subTomoya Sato
recoil transverse momentum widthTokyo Tech

SE-03A-Ȗ2-02*

Development of a cryogenic suspension system for TOrsion-Bar
Antennae (TOBA)

Ching Pin Ooi

UTokyoSE-03A-Ȗ2-03

Torsion-bar antenna for early earthquake alert

Yuka Oshima

UTokyoSE-03A-Ȗ2-04

Optimized Design of Quasi-phase-matched crystal for Spectrally-PureWu-Hao Cai
StateࠉGeneration at MIR Wavelengths Using Metaheuristic Algorithm

Tohoku U

SE-03A-Ȗ2-05

Experimental generalized measurement of qubits using a quantum
computer

Tohoku U

SE-03A-Ȗ2-06

14:50-16:10 SE-03A-Ȗ2

Tingrui Dong

Note: This program was created for fostering young VFLHQWLVWV. Presentations with asterisks (*) are excluded from awarding.

112

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į1-01

Lock-In Detected Ramsey Magnetometry with a Bulk Ensemble of Diamond
NV Centers for High-Sensitivity DC-Field Measurement

1

Sena Tsuchiya1, Daisuke Nishitani1, Yusei Aoki1, Takeharu Sekiguchi1, Takayuki Shibata2,
Takayuki Iwasaki1, and Mutsuko Hatano1,3

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2
DENSO CORPORATION
3
National Institutes for Quantum Science and Technology
tsuchiya.s.ag@m.titech.ac.jp

Introduction

Nitrogen-vacancy (NV) centers in diamond have attracted much attention as high sensitivity quantum magnetic sensors
that can be operated at room temperature. Our group has demonstrated magnetocardiography of living rats by combining
continuous-wave optically detected magnetic resonance (CW-ODMR) with lock-in (LI) detection1. However, further
improvement of DC-field sensitivity is necessary to detect magnetoencephalography signals. Double-quantum (DQ) Ramsey
magnetometry2 based on pulsed ODMR scheme is expected to achieve much higher sensitivity by improving both spindephasing time T2* and contrast2. Combination with LI detection of fluorescence intensity should reduce noise, remove signal
offset, and allow real-time measurement. In this study, we implemented LI detection under pulsed optical excitation anddetection with DQ Ramsey sequences to demonstrate the sensitivity improvement.
Methods
The diamond sample used was grown by HPHT with 12C-enriched source in NIMS, and the NV centers were created byelectron beam irradiation (1ൈ1017 cm-2) and annealing in QST. The concentrations of NV and P1 (substitutional nitrogen)centers were 0.05 ppm and 1.1 ppm. Fig. 1(a) shows our experimental setup. Pulsed optical excitation at 532 nm and theDQ-4-Ramsey sequence2 with resonant dual-frequency microwave (MW) were applied to a bulk ensemble of NV centers indiamond. The illumination volume was roughly (60ൈ160ൈ470) ȝm3. The fluorescence signal modulated by the DQ-4Ramsey sequence was detected and demodulated by a LI amplifier. The MW pulse width (0.22 s) for this sequence wascalibrated from the DQ-Rabi oscillation measurements.
Results and discussion
Fig. 1(b) shows the LI detected DQ-4-Ramsey fringes with microwave frequencies tuned to the central resonance of the14
N hyperfine triplet. The inset FFT spectrum shows clearly this triplet structure with the splitting doubled by the DQ
sequence. Fig. 1(c) shows MW frequency dependence of the Ramsey signal at a fixed free-precession time Ĳ using theSQ(single quantum)-2-Ramsey2 and DQ-4-Ramsey sequences. The DQ-4-Ramsey signal exhibits a 15% steeper slope thanthe SQ-2-Ramsey signal. The magnetic field sensitivity can be estimated from repeated measurements of the Ramsey signal
with a fixed ǻȞ at the steepest slope. We will discuss the sensitivity improvement factors such as lock-in detection forenhancing signal-to-noise ratio and DQ-4-Ramsey sequence for the Ramsey slope improvement.

(a)

IQ input

MW SG

MW SG

MW Amp

MW AmpMW antenna

Laser

MW

(b)

PXIe slots
AWG

PC

(c)

to PC
AOM

Lock-in Amp

diamond

PhotodiodeFIG. 1. (a) Experimental set up for LI detected Ramsey measurements. (b) DQ-4-Ramsey signal by LI detection at frequency detuning of ǻȞ = 0.0
MHz, in the time domain and frequency domain (inset). (c) Detuning sweep of the LI detected DQ-4-Ramsey (Ĳ = 0.46 ȝs) and SQ-2-Ramsey (Ĳ =0.40 ȝs). The dashed line represents the steepest slope of the DQ-4-Ramsey signal.

Acknowledgement
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395. We thank Dr. M. Miyakawa, Dr. T.
Taniguchi (NIMS), Dr. S. Ishii, S. Saiki, and S. Onoda (QST) for providing the diamond sample.
Reference
1
K. Arai et al., Commun. Phys. 5. 200 (2022). 2C. A. Hart et al., Phys. Rev. Appl. 15, 044020 (2021).

113

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į1-02
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114

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į1-03

Identification of current multipole sources frommagnetoencephalography data
Motofumi Fushimi1, Mutsuko Hatano2, Takaaki Nara3, and Masaki Sekino1

Department of Bioengineering, Graduate School of Engineering, The University of Tokyo
Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
3
Department of Information Physics and Computing, Graduate School of Information Science and Technology,
The University of Tokyo
motofumi-fushimi@g.ecc.u-tokyo.ac.jp
12

Introduction

In magnetoencephalography (MEG) source identification, current sources are typically modeled as equivalent current dipoles(ECDs). However, actual neural sources have non-negligible spatial pattern, which can be accounted for using equivalentcurrent multipoles (ECMs). We extend the previously proposed algebraic method for the multipole source identification in
the two-dimensional (2D) case [1] to the three-dimensional (3D) case to enhance applicability of the framework to therealistic MEG problem. This can also be seen as an extension of the 3D dipole and dipole-quadrupole identification method[2] to general-order multipoles.


Methods

By adopting the concentric sphere head model, the radial component of the magnetic field is represented by the current
source according to the Biot-Savart law as shown in Fig. 1. The multipole expansion of the equation relates the unknown
multipole source parameters (location and moment) to the MEG data [3]. We derived an algebraic equation for multipole
parameters, the detail of which will be shown in the presentation. We validated the proposed method by numericalsimulations with two distinct current quadrupoles and octupoles.


FIG. 1. Problem formulation of the MEG current source identification in the present study.

Results and Discussion

The proposed method could stably estimate both the two quadrupoles and octupoles, which has not been achieved in previous
methods, validating the efficacy of the method. In contrast, the results of the ECD model had huge errors because the ECD
model erroneously tries to explain MEG data resulting from multipoles by dipoles. The resulting figures will also bepresented in the conference.


Acknowledgements

This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.


Reference

T. Nara et al., Phys. Med. Biol., 52(13), 3859-3879 (2007).
T. Nara et al., Math. Probl. Eng., 2013, 413980 (2014).
3
G. Nolte et al., Biophys. J., 73(3), 1253-1262 (1997).

1
2

115

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į1-04

Optimization of simultaneous measurement of magnetic field and temperature
measurement by silicon vacancy quantum sensor using simultaneous resonanceTomoaki Tanaka1, Yuichi Yamazaki1, Kazutoshi Kojima2, and Takeshi Ohshima1
National Institutes for Quantum Science and Technology
National Institute of Advanced Industrial Science and Technology
tanaka.tomoaki@qst.go.jp
1

2

Background and Purpose

Silicon vacancies (VSi) in silicon carbide (SiC) have attracted great attention because we can measure magnetic field andtemperature in some devices by fabricating VSi in the devices1,2. Simultaneous measurement of magnetic field andtemperature using SiC-VSi quantum sensor requires simultaneous Optically Detected Magnetic Resonance (ODMR)
measurement of the ground and excited states. However, the ODMR contrast (= sensitivity) of the excited state is about oneorder of magnitude smaller than that of the ground state. So, the temperature measurement is time-consuming. To solve thisproblem, we have proposed and demonstrated a new temperature measurement method, Simultaneous Resonance (SR)ODMR, which based on the modulation of the ODMR contrast of the ground state by simultaneous resonance of the groundand excited states3. This method converts part of the contrast of the ground state into that of the excited state. It is necessary
to optimize the RF power ratio which is related to the contrast ratio between the ground and excited states to minimize themeasurement time in magnetic field and temperature (SR) simultaneous measurement. Therefore, the purpose of our study
is to optimize the power ratio of the RF using the simultaneous measurement by SR ODMR.
Methods and Results

VSi dots were fabricated on p-type 4H-SiC epitaxial thin film (5.6 μm) using a particle beam writing (ion species: He,energy: 0.5 MeV, irradiation dose: 3×105 /dots). The size and depth of the dots are 5×5 μm2 and ~1 μm, respectively. Threesignal generators were used for the measurements, one fixed at the resonance frequency of the ground state (70 MHz) for
SR, and the others swept near those of the ground and excited states (20-170, 300-600 MHz) for the ground state and SRODMR measurements, respectively.
Figure 1 shows the spectra of ground and SR excited states by ODMR simultaneous measurements. Signal intensities
indicated by red and blue arrows are observed. The former is a resonance of the ground state, and the latter is that of theexcited states. We can find that another dip indicated by green arrow around 500 MHz exists. The sweep condition indicatesthat this frequency corresponds to 70 MHz of the ground state measurement. This suggests that the resonance of the groundstate occurs in both the ground state and SR ODMR measurements. As a result of their competition, the dip appears at aroundthe 500 MHz on the SR ODMR side. We measured the changing of ODMR contrast of the ground and excited states when
we change the RF power of signal generators. The signal intensity was almost the same at the RF power ratio of 1:9 for SR
and ground state ODMR. At this condition, the contrast of SR is more than four times that of traditional excited statemeasurement. This suggests that we achieved faster measurement than conventional simultaneous ground and excited states
measurement.









FIG. 1. Simultaneous ODMR measurement of ground and SR excited states (GS and ES) spectra.

Acknowledgement

This work was supported by MEXT Q-LEAP Grant Number JPMXS118067395, ATLA Grant number JPJ004596, and
KAKENHI Grant Number 20H00355, 21H04553.

Reference

M. Niethammer et al., Phys. Rev. Appl. 6, 034001 (2016).
T. M. Hoang et al., Appl. Phys. Lett. 118, 044001 (2021).
3
Y. Yamazaki et al., The 69th JSAP Spring Meeting, 25a-E301 (2022).
1
2

116

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į1-05

Spin-Dependent Photocarrier Generation Dynamics in Electrically Detected
NV-Based Quantum Sensor
Hiroki Morishita,1,2 Naoya Morioka,1,2 Tetsuri Nishikawa,1,3 Hajime Yao,1,3Shinobu Onoda,4 Hiroshi Abe,4 Takeshi Ohshima,4 and Norikazu Mizuochi1,2Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
Center for Spintronics Research Network, Institute for Chemical Research, Kyoto University, Gokasho, Uji,
Kyoto 611-0011, Japan.
3
Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-Ku, Kyoto,
Kyoto, 615-8510, Japan.
4
National Institutes for Quantum Science and Technology, Takasaki, Gunma, 370-1292, Japan.
h-mori@scl.kyoto-u.ac.jp
1

2

A nitrogen-vacancy (NV) center in diamond is a promising candidate for room-temperature quantum sensors thanks to its
long electron spin coherence in ambient conditions [1]. In previous demonstrations, the NV electron spin was detected
optically, but another method called photoelectrically detected magnetic resonance (PDMR) is attracting attention. The
PDMR technique can read out NV electron spin [2-6] and coupled nuclear spins [7,8]. The electrical detection technique isadvantageous for developing and integrating quantum sensors and other quantum devices [7]. However, the mechanism forthe electrical detection of NV spins is not fully understood. In this study, we perform the pulsed PDMR measurements using
the ensemble of NV centers (concentration of ~ 1.4 ×1017 cm-3) created by 2 MeV electron irradiation with a fluence of 1×1017 cmí2 at 745 °C, followed by annealing at 1000 °C for 1 h in an argon atmosphere. We observe positive contrast in
PDMR (Fig. 1(a)) even though a negative PDMR contrast is usually observed. To discuss the sign of the PDMR contrast,
we numerically analyze the dynamics of photocarrier generation by NV centers using a seven-level rate model. We foundthat the sign of the PDMR contrast depends on the difference in the photocurrent generated from the excited states and themetastable state of NV centers.
Furthermore, we demonstrate AC magnetic field sensing using spin coherence with the PDMR technique. AC magnetic
field measurement with the PDMR technique is still challenging because the noise from a fluctuating magnetic environmentis greater than the measured signal. Using a phase-cycling-based noise-canceling technique to suppress the noise, we
demonstrate AC magnetic field sensing with the PDMR technique (Fig. 1(b)). We observe electrically detected AC magnetic
field sensing with a sensitivity of ~29 nT/ξHz. In this talk, we will discuss the mechanism of the NV center's electricaldetection and the sensitivity of the electrically detected AC magnetic field sensing.


FIG.1 (a) Pulsed PDMR spectrum. (b) AC magnetic field sensing with the PDMR technique

Acknowledgments

We thank T. Ono, T. Moriyama, and Y. Shiota for their technical help. This work was supported by MEXT Q-LEAP (No.
JPMXS0118067395), KAKENHI (No. 19H02546), and Kyoto University Nano Hub.


Reference

E. D. Herbschleb et al., Nat. Commun. 10, 3766 (2019). 2 E. Bourgeois et al., Nat. Commun. 6, 8577 (2015).
F. M. Hrubesch et al., Phys. Rev. Lett. 118, 037601 (2017). 4 M. Gulka et al., Phys. Rev. Applied 7, 044032 (2017)5
P. Siyushev et al. Science 363, 728 (2019). 6 T. Murooka et al., App. Phys. Lett. 118, 253502 (2021).
7
H. Morishita et al., Sci. Rep. 10, 792 (2020). 8 M. Gulka et al., Nat. Commun, 12, 4421 (2021).
1
3

117

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į1-06

Towards nanoscale zero- to ultralow-field NMR

Till Lenz , Omkar Dhungel1,2, Arne Wickenbrock1,2, Lykourgos Bougas1, John W. Blanchard2,3,
Gopalakrishnan Balasubramanian4, Anjusha Vijayakumar Sreeja5, Fedor Jelezko5, and Dmitry
Budker1,2,6
1,2*

Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
2
Helmholtz Institut Mainz, 55099 Mainz, Germany
3
Quantum Technology Center, University of Maryland, College Park, Maryland 20742, USA
4
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstr. 400, 01328 Dresden
5Institute for Quantum Optics, Ulm University, Albert-Einstein-Allee 11,89081 Ulm, Germany
6
Department of Physics, University of California, Berkeley, California 94720-7300, USA*tilllenz@uni-mainz.de, presenter
1

Abstract: Nuclear magnetic resonance (NMR) is a widely used tool in chemical analysis as well medical
diagnostics. While medical diagnostics is the most prominent branch of the NMR subfield magnetic
resonance imaging (MRI), chemical analysis is usually performed without imaging via NMR
spectroscopy. While we will focus on NMR spectroscopy, both techniques require strong expensive
magnets and are limited to sample sizes larger than the micron scale. To overcome these requirements
and limitations we propose nanoscale zero- to ultralow-field (ZULF) NMR [1,2]. To achieve the goal ofnanoscale ZULF NMR, we, together with our collaborators, demonstrated a technique formagnetometry with NV centers in the ZULF regime [3,4] (i.e. Zeeman interaction weaker than jcouplings) Moreover, we are exploring different potential samples and have identified some promising
candidates.

Reference[1] J. W. Blanchard, D. Budker, and Andreas Trabesinger, Lower than low: Perspectives on zero-to
ultralow-field nuclear magnetic resonance, Journal of Magnetic Resonance, 323, 106886 (2021) 1[2] D. Budker, Extreme nuclear magnetic resonance: Zero field, single spins, dark matter. . . , Journalof Magnetic Resonance, 306, Pages 66-68 (2019)[3] H. Zheng, J. Xu, G. Z. Iwata, T. Lenz, J. Michl, B. Yavkin, K. Nakamura, H. Sumiya, T. Ohshima,
J. Isoya, J. Wrachtrup, A. Wickenbrock, and D. Budker, Zero-Field Magnetometry Based on NitrogenVacancy Ensembles in Diamond, Phys. Rev. Applied, 11, 064068 (2019)[4] T. Lenz, A. Wickenbrock, F. Jelezko, G. Balasubramanian, and D. Budker, Magnetic sensing atzero field with a single nitrogen-vacancy center, Quantum Science and Technology, 6, 3 (2021)

118

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į1-07

Dipole-dipole interaction between NV- centers
Chikara Shinei1, Yuta Masuyama2, Masashi Miyakawa1, Hiroshi Abe2, Shuya Ishii2, Seiichi Saiki2,
Shinobu Onoda2, Takashi Taniguchi1, Takeshi Ohshima2 and Tokuyuki Teraji1
12

National Institute for Materials Science

National Institutes for Quantum Science and Technology
SHINEI.Chikara@nims.go.jp

Introduction
Negatively charged nitrogen vacancy center (NV-) ensemble with S=1 is a promising color center for highly sensitive
magnetometers.1 Dipole-dipole interaction (DDI) between the NV- center and paramagnetic defect is one of decoherence

mechanisms. In recent study, some studies showed the interaction between the NV- center and neutral substitutional nitrogen(Ns0) with S=1/2. The strength of DDI is usually expressed as the multiple of DDI coefficient and concentration ofparamagnetic defect. DDI coefficient of Ns0: ‫୒ܦ‬బ౩ is reported as 11.2 ms-1 ppm-1.1 For increasing the NV sensing sensitivity,
increasing of [NV-] is needed. Strength of dipole-dipole interaction between NV- centers is expected to be strong in increasingof [NV-]. The effect of interaction on coherence time T2 of NV- center is expected1 but is not still clear.
In this study, we investigated DDI coefficient of the NV- center. The DDI coefficient of the NV- center was evaluatedusing diamond single crystals with substantial amounts of NV- center being comparable to that of NS0.
MethodNitrogen doped diamond single crystals
used in this study were grown using either
HPHT synthesis or CVD method. After the
diamond growth, electron beam irradiation
was applied with the total fluences of 10171018 e/cm-2 to create vacancies in the
diamond. it was followed by vacuum
annealing at 1000ႏ for 2h to form NV
centersinthediamondcrystals.
Concentration of defects and T2 are evaluatedby EPR and Han echo method, respectively.

Result and Discussion

FIG. 1. (a) Relationship between T2 and concentration of Ns0.
(b) Relationship between T2 {NV-} and concentration of NV-.

First, we investigated dependence of [Ns0] on T2 of ensemble of NV- center. Fig. 1(a) shows relationship between T2 and[Ns0]. Most of the data indicates good inverse proportionality between T2 and [Ns0], with some exceptional data shown withsome deviation from solid line indicating. A larger ratio of [NVT] to [Ns0] would be associated with a tendency to greater
deviation. This result shows that the decoherence contribution of the spin bath of NV- and NV0 centers to the NV- center spinof interest cannot be ignored. Second, we observe ‫୒ܦ‬୚ష center using the data with relatively large [NVT]/[Ns0]. We also
obtained NV- component of T2: T2{NV-} using equation below,ଵଵషሾNV ି ሿ ൌ െ ൛‫୒ܦ‬బ౩ ሺሾNୱ଴ ሿ ൅ ሾNV ଴ ሿሻൟ.
ష ൌ ‫୒ܦ‬୚ ൈ்మ ሼ୒୚ ሽ்మ

Fig. 1(b) portrays relationship between T2{NV-} and [NV-]. The solid line represents the fitting function curve (ଵ்మ ሼ୒୚ష ሽൌwith respect to plotting data. We obtained ‫୒ܦ‬୚ష of 11.2 ms-1 ppm-1 through data fitting. This value is nearly‫୒ܦ‬୚ష ൈ
equal to that of ‫୒ܦ‬୚ష of 10 ms-1 ppm-1 estimated using the relation between DDI coefficient and spin multiplicity.1 We
observed DDI between NV- centers with [NV-] ranging from 0.2 ppm to 2 ppm.
Summary
We observed good inverse proportionality between T2{NV-} and [NV-]. This observation indicates that DDI between NVcenters occurs with [NV-] ranging from 0.2 ppm to 2 ppm.
ሾNV ି ሿ)Reference

J. F. Barry, J. M. Schloss, E. Bauch, M. J. Turner, C. A. Hart, L. M. Pham, and R. L. Walsworth, Rev. Mod. Phys. 92,
015004 (2020).
1

Acknowledgement

This work was supported by MEXT Q-LEAP (JPMXS0118068379 and JPMXS0118067395). T. Teraji acknowledges the
support of JST CREST (JPMJCR1773), MIC R&D for construction of a global quantum cryptography network(JPMI00316), and JSPS KAKENHI (Nos. 20H02187, 20H05661 and 19H02617). T. Teraji and S. Onoda acknowledge
the support of JST Moonshot R&D (JPMJMS2062).

119Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-ȕ1-01
Extension of dephasing time of ensemble NV centers with a continuous-excitation protocol
Ikuya Fujisaki1, Yuta Araki1, Yuji Hatano1, Takeharu Sekiguchi1, Takayuki Shibata2,
Takayuki Iwasaki1 and Mutsuko Hatano1
1
Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2
DENSO Corporation
fujisaki.i.aa@m.titech.ac.jp
Introduction
Quantum magnetic sensors based on nitrogen-vacancy (NV) centers in diamond are expected to be applied to biologicaland chemical applications with its high sensitivity. However, the DC magnetic field sensitivity of NV centers is stillinsufficient for further applications such as magnetoencephalography (MEG). We focused on CE-Ramsey1 (Continuous
Excitation Ramsey), which is not only advantages for miniaturization thanks to its experimental simplicity, but also has highsensitivity compared to conventional Ramsey. CE-Ramsey has a technical issue of long overhead time due to low laser
power limited to suppress optical broadening. Dephasing time ܶଶ‫ כ‬is a key parameter to improve sensitivity, but ܶଶ‫ כ‬oftypical bulk diamond is limited due to high nitrogen density. In this work, we developed a protocol that combines CERamsey with double quantum (DQ) coherence and spin bath driving (SBD)2 and demonstrated that dephasing time can beextended in the CE protocol.
Methods
We built a compact sensor-head with a CPC lens. Radio frequency system and microwave system are established tomanipulate spin bath and NV centers (Fig.1 (a)). We compared dephasing time between CE-SQ-Ramsey and CE-DQRamsey, with and without SBD. The diamond sample (ሾ ି ሿ̱ͲǤͺ , ሾୗ଴ ሿ̱ͺ ) was obtained by electron
irradiation (ͷ ൈ ͳͲଵ଻  ିଶ ) and vacuum annealing (2 hours) after CVD growth (110 thick) with ଵଶ -enrichedmethane on a type-IIa substrate.

Results and discussions
We first confirmed coherent control of P1 centers in the spin bath under CE protocol by measuring their spectra andtheir Rabi oscillations (Fig.1 (b)) with CE-DEER (Double Electron-Electron Resonance) sequences based on the CEHahn-Echo. We applied SBD to CE-DQ-4-Ramsey and compared dephasing time. The results showed that the dephasingtime is about 2-fold improved by applying DQ and SBD (Fig.1 (c)).

Acknowledgement
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.
We thank Dr. H. Kato (AIST) and Dr. S. Onoda, Dr. T. Ohshima (QST) for supplying diamond samples.
Reference
1. C. Zhang et al., Phys. Rev. Appl. 15, 1 (2021).
2. E. Bauch et al., Phys. Rev. X 8, 31025 (2018).

 (a)

(b)

(c)

Fig.1. (a) Experimental setup. Microwave and radio frequency are applied with wire and CPW(Coplanar
wave guide) respectively. (b) CE-P1 Rabi shows that coherent control of spin bath with CE protocol.
Pulse time of RF (radio frequency) is swept in CE-DEER sequences. (c) 2-fold extension of dephasingtime by applying DQ and SBD to CE-Ramsey.

120

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-ȕ1-02
Wide temperature operation of diamond quantum sensor
for electric vehicle battery monitoring
Keisuke Kubota1, Yuji Hatano1, Yuta Kainuma1, Daisuke Nishitani1,
Takashi Taniguchi2, Tokuyuki Teraji2, Shinobu Onoda3, Takeshi Ohshima3, Takayuki Iwasaki1,
and Mutsuko Hatano1,3

Department of Electrical and Electronic Engineering, School of Engineering, Tokyo institute of technology,
2-12-1 Ookayama, Meguro, Tokyo 152-8552, Japan
2
National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
3
National Institutes for Quantum Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japankubota.k.ai@m.titech.ac.jp
Introduction
1

The diamond quantum sensors containing NV centers for electric vehicle(EV) battery monitoring are realized [1].
Sensors for EV batteries require a wide range of operating temperatures; however, the dependence of the sensitivity of the
diamond quantum sensor system on its wide operating temperature has not been reported. Therefore, we measured themagnetic field sensitivity in the temperature range from -150° to 150°C to investigate its potential for battery monitoring.

Methods

The overall configuration of the measurement system used in the experiment, including the sensor head, is shown in Fig.1(a). The diamond sensor was a (111) HPHT crystal with the size of approximately 3.6 mm3. 11018 electrons/cm2 electron
beam irradiation and 1000 Υ for 1 hour annealing after it realized 5 ppm NV density. The diamond sensor was attached tothe top of the multimode fiber and the surrounding microwave antenna with copper belt was attached to realize the sensor
head with a size of 1 × 1 × 0.5 cm3. The green excitation light from the fiber, with an intensity of approximately 200 mW at
the end of the fiber, was irradiated to the diamond sensor. Liquid nitrogen and a heater were used to vary the temperature.

Result and discussion

Fig.1 (b) shows the temperature dependence of the measured sensitivity of the magnetic field. The sensitivity of
approximately 5 nT/Hz1/2 was confirmed in the temperature range of -150–150 °C in the measurement system at atmosphericpressure as shown in Fig.1 (a). This sensitivity means that 10 mA current can be measured almost in 500 Hz bandwidth in
the temperature range between -150 and 150 °C. The confirmed current sensitivity in such a wide temperature range makes
it suitable for the batteries that are currently used or under development. Fig.1 (c) shows the temperature dependence of theshot noise sensitivity obtained from the contrast, line width, and photodiode (PD) current. On the high temperature side, as
we had expected, the sensitivity deteriorated with increasing temperature. This deterioration is mainly due to the contrast
deterioration, which can be attributed to the accelerated initialization of the spin state due to the faster singlet state transition
rate [2]. On the low temperature side, we had expected that the sensitivity would be improved, but it deteriorated.
Deterioration in contrast was the main cause, but it is difficult to explain the physical reasons. Considering that the line width
is thinner at lower temperatures, water vapor condensation at microwave antenna may have increased antenna loss because
this experimental setup was open to the atmosphere.
This work was supported by MEXT Quantum Leap Flagship Program (Q-LEAP) Grant Number JPMXS 0118067395
and JPMXS0118068379.

References[1] Y. Hatano et al., Sci. Rep. 12, 13991 (2022)
(a)

(b)

[2] D. Toyli et al., Phys. Rev. X 2, 031001 (2012)(c)

Fig.1 (a) Structure of the entire sensitivity measurement system. The dimension of the sensor head was approximately 1× 1 × 0.5 cm3. (b) Temperature dependence of the measured sensitivity. It was confirmed that the current sensitivity
requirements for EV batteries were obtained in the measured temperature range. (c) Measured temperature dependence ofshot noise sensitivity obtained from contrast, line width, and PD current.

121Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

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122

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-ȕ1-04

Attempts to generate entanglement state between dipolar coupled NV centerscreated by molecular implantation
Kosuke Kimura1,2, Shinobu Onoda1, Keisuke Yamada1, Wataru Kada2, Tokuyuki Teraji 3,
Junichi Isoya4, Nozomu Kosuge1,2, Tomoya Baba1,2, Osamu Hanaizumi2, and Takeshi Ohshima1
National Institutes for Quantum Science and Technology
Graduate School of Science and Technology, Gunma University
3
National Institute for Materials Science1

2

4Faculty of Pure and Applied Sciences, University of Tsukuba
kimura.kosuke@qst.go.jp, t222d002@gunma-u.ac.jp.

Introduction

Generating quantum entanglement states is one of the most important steps in quantum technologies such as quantum
information processing and quantum sensing, etc. The generation of entanglement states has been demonstrated on thevarious quantum systems. Among them, the entanglement between some solid-state spin qubits has the generation advantage
at room temperature. Generation of entanglement state between Nitrogen-Vacancy (NV) centers in diamond, known as solidstate electron spin qubits, has been demonstrated by Double Electron-Electron Resonance (DEER)1,2. The decoherence ofNV center limits the fidelity of entanglement state. It is expected that the short free evolution time for entanglement (ʹ߬௘௡௧ )reduce the limitations caused by decoherence. The spin state reaches the maximum quantum entanglement state at the freeevolution time ʹ߬௘௡௧ ൌ ͳȀ߭ௗ௜௣ by DEER, where ߭ௗ௜௣ is dipole coupling strength. By making the dipole-dipole interaction
as strong as possible, high fidelity due to short free evolution time is expected. We have created the strongly coupled NV
centers by molecular ion implantation3,4. In this study, we report the generation of entanglement state between dipolar
coupled double NV centers created by implanting C5N4Hn ions. In addition, we report the attempts to shorten ʹ߬௘௡௧ bychanging DEER pulse sequence.

Experiments and Results

To create dipolar coupled NV centers, C5N4Hn ions were accelerated at
65 keV and implanted into diamond. A C5N4Hn ion decomposes into
individual atoms by collision with diamond, and each nitrogen atom is
implanted 9±4 nm apart. The implanted nitrogen atom was combined witha vacancy by annealing process (1000°C, 2h) to create NV centers.
The created NV centers were observed using confocal fluorescencemicroscopy (CFM). The measurement of DEER was performed with a
532 nm pulsed laser and pulsed microwaves at room temperature in thestatic magnetic field (FIG. 1). The electron spins of two NV centers withdifferent resonance frequencies (2.6279 GHz for NVA, 2.6778 GHz for
NVB) able to be manipulated individually. Preparing both NV centers instate ห݉ௌǡ஺ ൌ Ͳǡ ݉ௌǡ஻ ൌ Ͳൿ by optical pumping, an echo measurement iscarried out on NVA. To apply ʌ/2 pulse on NVB before the second ʌ/2 on
NVA, fluorescence is a periodical signal of ܿ‫ݏ݋‬൫ʹߨ߭ௗ௜௣ ߬൯. The result of
the DEER measurement is shown in FIG. 2. The measured ߭ௗ௜௣ was 99.9
kHz and ʹ߬௘௡௧ ൌ ͳȀ߭ௗ௜௣ was calculated as 10 ȝs. In the presentation, theentanglement generation with other pulse sequences will be discussed.

Initialization

NVA

NVB

ȷ/2

Readout

ȷ

ȷ/2
ĳ
ȷ/2

FIG. 1 DEER pulse sequence.
Ǎdip=99.9 kHz

Acknowledgments

This work was supported by JST Support for Pioneering Research
Initiated by the Next Generation JPMJSP2146, JSPS KAKENHI No.
FIG. 2 Typical DEER spectrum.
21H04646, 20H02187, 20H05661, JST moonshot R&D Grant Number
JPMJMS2062, MIC R&D for construction of a global quantum
cryptography network JPMI00316, and MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) Grant Number
JPMXS0118067395 and JPMXS0118068379.

References
1
3

P. Neumann, et al., Nat. Phys. 6, 249 (2010). 2 F. Dolde, et al., Nat. Phys. 9, 139 (2013).
M. Haruyama, et al., Nat. Commun. 10, 2664 (2019). 4 K. Kimura, et al., Appl. Phys. Express 15, 066501 (2022).

123Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-ȕ1-05

Charge stability of shallow single NV centers in p-type diamond
Taisuke Kageura1,2, Yosuke Sasama1, Chikara Shinei1, Tokuyuki Teraji1,
Keisuke Yamada3, Shinobu Onoda3, and Yamaguchi Takahide1
National Institute for Materials Science (NIMS)
National Institute of Advanced Industrial Science and Technology (AIST)
3
National Institutes for Quantum and Radiological Science and Technology (QST)
kageura.taisuke@aist.go.jp
12

Introduction

A stable negatively charged state of nitrogen vacancy (NV) centers in diamond is important for diamond quantum
applications such as highly sensitive quantum sensing and high-performance quantum information processing. However, it
has been found that the charge state of single NV centers near the surface, called shallow single NV centers, is quite unstablecompared with NV centers in bulk1. Shallow single NV centers are significant to realize high-performance quantum devices
such as nanoscale NMR, so the origin of the charge instability needs to be revealed. Here we investigated how the presenceof small amounts of boron acceptors in bulk and surface states affect the charge stability of shallow single NV centers2.

Results and Discussion

We prepared four lightly boron-doped diamond thin films ([B]ӊ1×1015 cm-3,[N]<6×1011 cm-3) synthesized by microwave plasma chemical vapor deposition
method and formed single NV centers at about 3.6 nm from the diamond surface
by ion implantation. We have investigated the charge-state stability of the shallow
single NV centers by using photoluminescence spectra and optically detectedmagnetic resonance (ODMR) measurements. Surprisingly, we found thatnegatively charged state can be created despite the existence of boron acceptors;
Among 20 NV centers for which CW-ODMR was measured, 19 NV centers showed adecrease in fluorescence intensity at a frequency corresponding to the appliedmagnetic field of 1-2 mT. This negatively charged state could not be explained by
the conventional band-bending model, but it could be explained by photoexcitationinduced by green laser irradiation. Then we evaluated the charge stability underpulse measurement in the presence of laser non-irradiation time by Rabi oscillation
contrast values (Fig. 1). Clear Rabi oscillations were observed except for the
sample with higher boron concentration ([B]=1×1015 cm-3) and acid boiled surface,which means that negatively charged state can be created even under pulse
measurement. The variation of contrast values in Fig. 1(b) indicates the differencein charge stability of individual NV centers. This charge instability in lightly doped
diamond can be explained by electron transfer between the NV center and the local
environment. The charge stability is determined by whether the donor or theacceptor is closer to the NV center.
This study provides a new insight into the charge stability of a single NV centerin low-doped diamond and contributes to the further development of NV quantum
devices.
This work was partially supported by MEXT Q-LEAP Grant Number
JPMXS0118068379 and JPMXS0118067395, JST CREST (JPMJCR1773), JST
Moonshot R&D (JPMJMS2062), MIC R&D for construction of a global quantum
cryptography network (JPMI00316), JSPS KAKENHI (No. 20H02187,
20H05661, 19H02617 and 21J01804).

Reference
1
2

D. Bluvstein et al., Physical Review Letters, 122, 076101 (2019)
T, Kageura et. al, Carbon, 192, 473 (2022).

FIG. 1. (a) Typically observed
Rabi oscillations and (b) the
distributions of Rabi contrast124Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-ȕ1-06
Room-temperature electrical detection of nuclear spins in silicon carbide
Naoya Morioka1,2, Tetsuri Nishikawa1, Hiroshi Abe3, Hiroki Morishita1,2,
Takeshi Ohshima3, and Norikazu Mizuochi1,2Institute for Chemical Research, Kyoto University
Center for Spintronics Research Network, Institute for Chemical Research, Kyoto University
3
National Institutes for Quantum Science and Technology
morioka.naoya.8j@kyoto-u.ac.jp
12

Spin-active color centers in silicon carbide (SiC) are promising candidates for scalable quantum sensors and quantum
information devices operating at room temperature due to their excellent spin coherence properties and the maturity of SiC's
wafer-scale semiconductor technology. By making use of the excellent controllability of semiconductor properties anddevice operation of SiC, the realization of electrical detection of spin information in SiC can benefit in developing integrated
quantum devices compared with conventional optical spin detection techniques. Recently, electrical detection of electron
spins of the V2 center in 4H-SiC1 was reported by photoelectrically detected magnetic resonance2 (PDMR). However, in theprevious demonstration, the PDMR spectra of V2 centers were broad due to the inhomogeneous magnetic field caused bymagnetized Ni electrodes, which is a typical ohmic contact material for SiC. The broad linewidth inhibited resolving thesignal of nuclear spins, which are useful resources as quantum memories for quantum information processing3 andsensitivity-enhanced quantum sensing.4 In this study, we optimized the contact and the device structures, and we obtained
the PDMR spectrum of an ensemble of V2 centers with a linewidth of 2.8 MHz, which is narrow enough to observe thehyperfine split resonance peaks coupled to the next-nearest-neighbor (NNN) 29Si nuclear spins (Fig. 1). By addressing thehyperfine split peaks, nuclear-spin-state-dependent spin control and its electrical detection are possible. By applying thesetechniques, the nuclear magnetic resonance signal of 29Si was successfully detected electrically at room temperature with
PDMR-based electron-nuclear double resonance (ENDOR) (Fig. 2).5 This is an achievement of electron spin coherence andnuclear spin detection in an identical device. In the ENDOR spectrum in Fig. 2, three peaks were observed, probably
originating from three nonequivalent NNN sites.6 These results suggest that room-temperature PDMR would enable selective
coherent control of nuclear spins, facilitating the development of electrically-driven integrated quantum devices.

FIG. 1. PDMR spectrum of V2 centers in 4HSiC.

FIG. 2. PDMR-ENDOR spectrum of NNN 29Si
nuclear spins coupled to V2 centers in 4H-SiC.

Acknowledgments
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395, JSPS KAKENHI Grant Numbers
JP20H00355, JP21H04553, JP21K20502, and JP22H01526, JST SPRING Grant Number JPMJSP2110, and Kyoto
University Nanotechnology Hub in MEXT ARIM project.
Reference1
M. Niethammer et al., Nat. Commun., 10, 5569 (2019).
2
E. Bourgeois et al., Nat. Commun., 6, 8577 (2015).
3
C. E. Bradley et al., Phys. Rev. X, 9, 031045 (2019).
4
M. Pfender et al., Nat. Commun., 10, 594 (2019).
5
T. Nishikawa et al., Appl. Phys. Lett., accepted (2022).
6
V. Ivády et al., Phys. Rev. B, 96, 161114 (2017).

125

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-ȕ1-07(Near) zero-field cross-relaxation features for ensembles of NV centers indiamondOmkar Dhungel1, Till Lenz1, and Dmitry Budker1,21Johannes Gutenberg University Mainz, Germany
Helmholtz Institute Mainz 55128, Germany

Department of Physics, University of California, Berkeley, California 94720-300, USA
budker.uni-mainz.de2

Conventional magnetometry using NV centers in diamond relies on the application of microwaves and bias magnetic field.
However, there are applications, for example, the study of high-temperature superconductors, zero- to ultralow-field (ZULF)
NMR, investigation of biological samples, and magnetic materials where either the microwaves or the bias magnetic fieldmight disturb the system. To overcome such limitations, we study the zero-field cross-relaxation feature [1] for ensemblesof NV centers. A study of cross-relaxation features with respect to the sample cut and, NV density will be presented. Multiple
cross-relaxation features [2,3] are observed when transverse field is present and these features follow a specific pattern when
the azimuthal angle of a transverse field is changed, which is useful for vector-magnetometry applications.


Reference

S. Anishchik, V. Vins, A. Yelisseyev, N. Lukzen, N. Lavrik, and V. Bagryansky, “Low-field feature in the magnetic spectraof nv- centers in diamond,” New Journal of Physics, vol. 17, no. 2, p. 023040, 2015.
1

R. Akhmedzhanov, L. Gushchin, N. Nizov, V. Nizov, D. Sobgayda, I. Zelensky, and P. Hemmer, “Microwave-freemagnetometry based on cross-relaxation resonances in diamond nitrogen-vacancy centers,” Physical Review A, vol. 96, no.
1, p. 013806, 2017.
2

R. Akhmedzhanov, L. Gushchin, N. Nizov, V. Nizov, D. Sobgayda, I. Zelensky, and H. Philip, “Magnetometry by crossrelaxation-resonance detection in ensembles of nitrogen-vacancy centers,” Phys. Rev. A, vol. 100, p. 043844, Oct 2019.
3

126

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ1-01

Evaluation of a superconducting nanowire single photon detector for midinfrared wavelengths

Satoru Mima 1, Fumihiro China 1, Masahiro Yabuno 1, Shigeyuki Miyajima 1, Shigehito Miki 1, 2,
Yuki Gama 3, Toshiyuki Tashima 3, Masaya Arahata 3, Yu Mukai 3, Ryo Okamoto 3, Shigeki
Takeuchi 3 , Hirotaka Terai 1
1

Advanced ICT Research Institute, National Institute of Information and Communications Technology
2
3

Graduate School of Engineering, Kobe University

Graduate School of Engineering, Kyoto University
mima@nict.go.jp

Introduction

Superconducting nanowire single photon detectors (SNSPDs) have attractive features such as high efficiency, low jitter,
low dark counts, and high counts rates, and are expected to be applied in various fields. Recently, quantum technologies
utilizing photons in the mid-infrared region have attracted much attention[1]. However, there are no single-photon detectors
in the mid-infrared wavelengths. SNSPD is one of best candidate for high detection efficiency in the mid-infrared region.
In the mid-infrared region, the photon energy is smaller than in the near-infrared region, so the superconducting thin film
used in the detector must be thinner and superconducting nanowire must be narrower. In addition, for highly efficient midinfrared photon detection, the introduced light must be efficiently absorbed by the superconducting nanowire. We employ
an approach to enhancing the optical absorptance at target wavelength is integrating the nanowire with the dielectric
multilayer cavity[2]. In this study, superconducting nanowire were fabricated on a dielectric multilayer of Ta2O5 and Si films
designed to maximize light absorption in the mid-infrared region and evaluated.
We cooled down the fabricated detector by a sorption refrigerator capable of cooling down to 0.8 K and evaluate theoptical properties using a QCL light source (wavelength ~ 4.3 ȝm) in the mid-infrared region. We reduced optical efficiency
between the fiber and the superconducting nanowire for the evaluation of internal efficiency because of the intensity of
blackbody radiation in the mid-infrared region. The figure 1 shows the dependence of the internal efficiency of thesuperconducting nanowire on the bias current measured at different intensities of the mid-infrared light source. We also
evaluated the optical efficiency of the same superconducting nanowire in the near-infrared region (1300 nm to 1600 nm) andconfirmed that the spectra are consistent with the design.

Acknowledgment

This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067634.

Reference

R. H. Hadfield, Nat. Photon., 3, 696–705 (2009).
T. Yamashita, K. Waki, S. Miki, R. A. Kirkwood, R. H. Hadfield, H. Terai, Sci rep., 6, 35240 (2016).
1
2

Fig 1. Comparison of the intensity dependenceof the internal efficiency in the mid-infrared.

127Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ1-02

Efficient superconducting nanostrip single-photon detectors for 2 Pm
wavelength
Fumihiro China1, Satoru Mima1, Shigehito Miki1,2, Masahiro Yabuno1, Shigeyuki Miyajima1 and
Hirotaka Terai11Advanced ICT Research Institute, National Institute of Information and Communications Technology
2

Graduate School of Engineering, Kobe University
f-china@nict.go.jp

Introduction

In recent years, single-photon detection technology in the mid-infrared wavelength region has attracted attention. In
particular, at the 2 Pm wavelength band, highly efficient single-photon detectors are required for various applications suchas light detection and ranging (LIDAR), satellite-based quantum communications, and silicon-based quantum optics.
However, semiconductor avalanche photodiodes and photomultiplier tubes are limited to a sensitive wavelength ofapproximately 1.8 Pm by the energy gap of the semiconductor. On the other hand, superconducting nanostrip single-photon
detectors (SNSPDs) are promising detectors because of their wideband sensitivity including the mid-infrared region [1]. To
obtain high system detection efficiency (SDE) using SNSPDs, the following three factors should be maximized: optical
coupling efficiency, optical absorptance, and internal detection efficiency. The optical coupling efficiency can be maximized
by increasing the active area of the SNSPD, and the optical absorptance of superconducting nanostrips is improved by
implementing an optical cavity in the SNSPD. The internal detection efficiency can be improved by optimizing nanostrip
parameters such as nanostrip width and thickness. In this study, we developed SNSPDs with a dielectric multilayer cavity(DMC) and attempted to maximize the three factors to achieve high SDE in the 2 Pm wavelength.

Device design and experimental results

We developed NbTiN-SNSPDs with a DMC. Figure 1 shows the schematic of designed SNSPDs with a DMC comprisedof 11 periodic SiO2/Si bilayers on a Si wafer. Each dielectric layer of DMC is one-quarter of the optical thickness for the
2 Pm wavelength. The DMC enhances the optical absorptance by concentrating the electric field of incident photons on thenanostrips. In the simulation results by finite element analysis, we confirmed that the optical absorptance at the 2 Pm
wavelength reaches over 99%. Based on the SNSPD designs, we fabricated NbTiN-nanostrips with a line width ofapproximately 110 nm on the DMC. The active area of the fabricated SNSPDs, 30 Pm × 30 Pm, is enough larger than themode field diameter of a single mode fiber for the 2 Pm wavelength band. Subsequently, we tested the fabricated SNSPDs
using a sorption-based cryocooler with an operating temperature of 0.77 K and an optical system composed of a laser source,
a beam splitter, valuable optical attenuators (VOAs), neutral-density (ND) filters, a polarization controller, and power meters.
We adjusted the optical input power to -110 dBm using three VOAs and two ND filters, and all five attenuators were carefully
calibrated before SDE measurements. Figure 2 shows the measurement results of SDE and the dark count rate (DCR) of the
SNSPD. We succeeded to demonstrate a high SDE of 79% at a 2 Pm wavelength. In addition, we estimated the measurement
uncertainty of SDE as ±5.075% by measuring all possible uncertainties of VOAs, ND filters, laser power, the count rate,
DCR, and a power meter.

Acknowledgment

This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067634.

Reference

F. Marsili et al., Nano Lett, 12, 4799-4804 (2012).
1

FIG. 1. Schematic of the device structure of
an SNSPD with a DML.

FIG. 2. Bias current dependences of system
detection efficiency (SDE) and dark count rate
(DCR).

128

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ1-03

Effect of pump laser linewidth on nonlinear quantum interferometric fringes
1

Jasleen Kaur1, Yu Mukai1, Ryo Okamoto1 and Shigeki Takeuchi1*

Department of Electronic Science and Engineering, Graduate School of Engineering, Kyoto University*takeuchi@kuee.kyoto-u.ac.jp

Introduction

 Infrared spectroscopy is a non-invasive technique used for the identification of materials by analyzing their infrared
spectrum. This technique finds applications in chemical industries, environmental sensing, and life sciences, etc. However,conventional infrared spectroscopy techniques suffer from low directivity of infrared sources and thermal background noise
deteriorating the sensitivity of IR detectors. Therefore, quantum infrared spectroscopy (QIRS) [1] is being widely
investigated as this quantum sensing technology enables IR spectroscopy using a light source and detector in the visible
region. In this technique, by utilizing the quantum correlation between visible and IR photon pairs and the quantum
interference of their generation processes, we can extract the optical properties of the IR absorptive sample.
The generation of correlated photon pairs in QIRS relies on the spontaneous parametric down-conversion (SPDC) process.
Since the current QIRS experiments have been demonstrated using a continuous wave (CW) laser [2,3], the probe photon
flux generated is low, leading to an inferior signal-to-noise ratio (SNR) thus limiting the sensitivity of this technique.
Achieving high generation efficiency of the PDC process can aid in increasing the SNR of the system. One of the possible
ways is to use a short pulse pump laser as the excitation source. The temporal confinement of energy in a pulse laser helps
in increasing the parametric gain of the PDC process. However, it is important to note that the pulse laser possesses a finite
spectral linewidth which leads to a partial frequency correlation between the generated photon pairs, leading to increased
distinguishability between the photons, thus lower interference contrast.
In this work, we report a quantitative analysis of how the pump laser linewidth affects the nonlinear quantum
interferometer. As shown in fig.1, we excite a nonlinear quantum interferometer with both CW and pulse laser sources andcompare the contrast of fringes using a dispersive spectrometer. We further derive the mathematical relationship between
the interferometric pattern obtained by CW and pulse laser.

FIG. I. Schematic of the nonlinear quantum interferometer

Reference
1

D. A. Kalashnikov et al. Nat. Photonics, vol. 10, no. 2, p. 98–101 (2016)2

Y. Mukai et al. Phys. Rev. Appl., vol. 15, no. 3, p. 034019 (2021)

3

P. Kaufmann et al. Opt. Express, vol. 30, no. 4, p. 5926 (2022)

Acknowledgment

This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067634, JST-CREST Grant Number
JPMJCR1674, JSPS KAKENHI Grant Number 21H04444, and WISE Program, MEXT

129

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

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130Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ1-05

Optical trapping and movement control of gold nanoparticles onan optical nanofiber
Rui Sun1,2, Yining Xuan1,2, Soyoung Baek1, and Keiichi Edamatsu1

Research Institute of Electrical Communication, Tohoku University
Department of Electronic Engineering, Graduate School of Engineering, Tohoku University
1

2

sun.rui.p6@dc.tohoku.ac.jp

Introduction

Optical nanofiber has drawn lots of interests in past few years as a promising tool in quantum optics and quantum
metrology for its unique properties1,2. Our research focus on the single photon source based on quantum-dot-goldnanoparticle coupled system on optical nanofiber3. With this experimental system, we have realized a single photon source
which is much better than directly exciting the quantum dot with laser. For instance, significant Purcell enhancement of thesingle photon emission rate was observed4.
However, the current experimental system still has some drawbacks. The position of gold-nanoparticle on nanofiber isentirely random, which makes it difficult to quantitatively study the single-photon emission rate. Thus, we propose a noncontact method to control the position of a gold-nanoparticle on the nanofiber. In the past research, we have realized tocontrol the motion of liposome particles in solution by changing the intensity of evanescent light field on the optical nanofiber
surface5. Here, following a similar approach, we report on a protocol to achieve the control of gold nanoparticles on an
optical nanofiber to further improve the properties of single photon source. As shown in Figure 2, the optical nanofiber isimmersed in the solution containing gold nanoparticles, and 785 nm laser and 530 nm laser are injected at both ends of thenanofiber respectively. 785 nm laser is used to generate evanescent light field, and 530 nm laser is used to detect the
movement of the gold nanoparticles on the surface of optical nanofiber. By adjusting the laser intensity, we can control the
movement of the gold nanoparticles on the nanofiber surface. We will introduce optical tweezer to this system to achieve
more precise position control of gold nanoparticles.
This work is supported by MEXT Q-LEAP Grant Number JPMXS0118067581.

FIG. 1. The movement of a liposome
along the nanofiber5.

FIG. 2. The scheme of experimental setup.

Reference
M. Joos, A. Bramati, and Q. Glorieux, Opt. Express, 27, 18818-18830 (2019).
C. Lee, M. A. Buyukkaya, S. Harper, S. Aghaeimeibodi, C. J. K. Richardson, and E. Waks, Nano Letters, 21, 323-329(2021).
3
M. Sadgrove, M. Sugawara, Y. Mitsumori and K. Edamatsu, Sci Rep, 7, 17085 (2017).
4
M. Sugawara, Y. Xuan, Y. Mitsumori, K. Edamatsu and M. Sadgrove, Phys. Rev. Research, (in press) (2022).
5
T. Yoshino, D. Yamaura, M. Komiya, M. Sugawara, Y. Mitsumori, M. Niwano, A. Hirano-Iwata, K. Edamatsu, and M.
Sadgrove, Opt. Express, 28, 38527-38538 (2020).

1
2

131

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ1-06

Electromagnetic-field analysis of the plasmon-enhanced single photon emitterson an optical nanofiber
Yining Xuan1,2, Rui Sun1,2, Soyoung Baek1, and Keiichi Edamatsu1

Research Institute of Electrical Communication, Tohoku University
Department of Electronic Engineering, Graduate School of Engineering, Tohoku University
xuan.yining.t8@dc.tohoku.ac.jp
12Single photon emitter has many applications in quantum information, communication, and metrology. Therefore, brightsingle photon emitters with enhanced quantum efficiency are very important for practical quantum applications and havebeen studied using various systems [1]. To achieve an enhanced, polarized single photon source that can be coupled into thefiber network directly, we studied on a gold nanoparticle-quantum-dot (GNP-QD) coupled system [2,4], as shown in Fig.1.
The single photon source in this research is based on a semiconductor quantum dot (QD) with the emission wavelengtharound 800 nm. The surface plasmon resonance of gold nanoparticles (GNP) provide large Purcell enhancement relative toconventional cavities and can also provide enhancement of degree-of-polarization (DOP) depending on the type ofnanoparticle. In addition, optical nanofibers have the advantages of low optical loss when coupling to conventional fiber
networks, and low cost as they can be fabricated from standard single mode optical fibers. Furthermore, through theevanescent field of the nanofiber, photons from QDs can be coupled directly into the nanofiber and hence an optical fiber
network.
To understand the distribution of electric field and the impact of incident light on gold nanoparticles on the nanofiber, we
carried out electromagnetic-field analysis (FDTD: Finite-difference time-domain method). We analyze the background field
distribution, reflection coefficient, absorption and scattering cross section of gold nanoparticles on the fiber surface at various
incident angles. Through the analysis of electric field distribution and localized surface plasmon response of gold
nanoparticles in Fig.2, the performance of gold nanoparticles on the surface of nanofiber is obtained and discussed. The
single photon source with GNP-QD structure can enhance the luminous efficiency of quantum dot due to the Purcell effect.
We plan to add a quantum dot in the vicinity of the gold nanoparticle and perform the simulation.

This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067581.
     FIG. 1. SEM image of the quantum-dot-gold-nanorod
coupled system on an optical nanofiber.

FIG. 2. Localized plasmon resonance of gold
nanorod using FDTD simulation.



Reference

H. J. Kimble, Nature, 453, 7198 (2008).
M. Sadgrove, M. Sugawara, Y. Mitsumori, and K. Edamatsu, Sci. Rep., 7, 17085 (2017).
3
M. Sugawara, Y. Mitsumori, K. Edamatsu, and M. Sadgrove, Opt. Express, 28, 18938 (2020).
4
M. Sugawara, Y. Xuan, Y. Mitsumori, K. Edamatsu, M. Sadgrove, Phys. Rev. Research, (in press) (2022).
1
2

132

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ1-07

Ultrafast measurement of biphoton wave packets using optical Kerr gating
Takahisa Kuwana1, Masahiro Yabuno2, Fumihiro China2, Shigehito Miki2, Hirotaka Terai2,
Peter J. Mosley3, Rui-Bo Jin4 and Ryosuke Shimizu1
1The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, Japan

Advanced ICT Research Institute, National Institute of Information and Communications Technology,

2588-2 Iwaoka, Nishi-ku, Kobe 651-2492, Japan

Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, Bath, BA2 7AY, UK

3

4Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, China

k2133039@gl.cc.uec.ac.jp

Introduction

Single-photon detection is of importance for quantum information and sensing technologies. Improving the temporal
resolution in single-photon detection is essential for the further development of quantum technologies. Currently, asuperconducting nanowire single-photon detector has achieved ~3 ps temporal resolution, which is the best temporal
resolution as far as we know. However, there is a trade-off between detection efficiency and temporal resolution. Thus,
extending into the femtosecond range is challenging without a catastrophic reduction in detector efficiency. On the other
hand, optical gating with ultrafast laser pulses can efficiently detect photons with high temporal resolution. Up to now, wedeveloped an ultrafast single-photon detector using an optical Kerr gating (OKG) and demonstrated the single-photon
detection with 224s9 fs temporal resolution under low-gating power consumption (~20 mW)1. However, no demonstrationof a two-photon detection by the OKG has been reported. In this work, we present the development of our OKG system to a
two-photon detection toward joint temporal intensity (JTI) measurements.

Experiment'W А
Figure 1 shows the schematic diagram of the experimental 9HUWLFDO3RODUL]DWLRQ'HOD\/LQH
setup. Our PCF was specially designed to minimize the group
6DJQDF ,QWHUIHURPHWHU
velocity difference between the photons with the center'W⾫
wavelength of 1584 nm and the gating pulse with the wavelength +RUL]RQWDO3RODUL]DWLRQ3&)'HOD\/LQH
of 792 nm for efficient cross-phase modulation. Ultrafast pulses
from a mode-locked Ti:sapphire laser operating at the663'
wavelength of 792 nm were divided by a polarization beam
7L6 /DVHU
7&63&
splitter. One is sent to a periodically poled KTP (PPKTP) crystal QPIV#0+]
663'
to generate biphotons in a type-II phase-matching condition and+:34:3)LOWHU 7L6 FXW 0LUURU'&0
the other is used for gating pulses of the OKG system.
FIG.
1.
JTI measured our OKG system
Biphotons generated via PPKTP crystal were led to the OKG
system with the Sagnac interferometer configuration. Photons were propagated in either clockwise (CW) or
counterclockwise (CCW) directions. Only the photon wave packet in the CW propagation was copropagated with the gating
pulse. Then, a nonlinear phase shift by the optical Kerr effect was added to the photon overlapped with the gating pulse in
the PCF. In the case that the phase difference between CW and CCW propagation of the Sagnac interferometer is not zero,a portion of the photons are outputted to the detection port. Eventually, we can measure the envelope of the wave packet bysweeping the relative delay between the photon and the gating pulses. With the help of polarization multiplexing, wedeveloped our system to the two-photon detection. We reconstruct the JIT from coincidence counts of our Kerr gating system.
V

H

fFP

G%&RXSOHU

33.73

RXWSXW
SRUW

Results and discussion

Figure 2 shows the measured JTI. We can clearly see the two-photon temporal
distribution with a negative correlation. This is the first experimental observationof the JTI by the OKG. We achieved the maximum signal-to-noise ratio with agating power of 50 mW, meaning that the order-of-magnitude improvement of
the gating power consumption compared to the up-conversion method2.

Acknowledgment

This work was
JPMXS011806924.

Reference

supported

by

MEXT

Q-LEAP

Grant

NumberM. Yabuno, R. Shimizu , et al., Opt. Express 30, 4999-5007 (2022).
2
R.-B. Jin, R. Shimizu , et al.. Phys. Rev. Appl. 10, 034011/1-11 (2018).
1

FIG. 2. JTI measured our OKG system

133

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į2-01

Growth of thick CVD diamond films containing aligned nitrogen-vacancy
centers for high-sensitivity quantum sensors
Takeyuki Tsuji1, Takayuki Iwasaki1, and Mutsuko Hatano1

1

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
tsuji.t.ac@m.titech.ac.jp

A large volume of CVD diamond films containing aligned
nitrogen-vacancy (NV) centers lead to highly sensitive quantum
sensors. To form perfectly aligned NV centers, diamonds need to
be grown using lateral growth in the [1 �1 �2] direction.[1] It isnecessary to cut and polish the diamond substrate at amisorientation angle (ߠ௠௜௦ ) to create the steps, as shown in Fig. 1.
Geometrically, as ߠ௠௜௦ increases, the maximum thickness of the
diamond film increases, as shown in Fig. 1. For example, if a 1
mm2 diamond substrate is polished at ߠ௠௜௦ =10°, the maximum
film thickness is 1 mm × sin(10°) � 170 μm, while at ߠ௠௜௦ =0.5°,
the maximum film thickness is 1 mm × sin(0.4°) � 7 μm.
Fig.1. Differences in the maximum film thicknesses
Therefore, ߠ௠௜௦ is a key parameter in determining the thickness
for different misorientation angles (ߠ௠௜௦ ).
of the diamond films. In this study, the dependence of the growthrate and NV center properties on ߠ௠௜௦ (= 0.4°–9.9°) wasinvestigated for synthesizing a thick diamond film containingaligned NV centers.
Diamond films containing NV centers were grown on Ib (111)diamond substrates (1 mm × 1 mm × 0.3 mm). The surfaces of the
diamond (111) substrates were polished in the [1 �1 �2] direction atߠ௠௜௦ of 0.4(1) °, 2.7(1) °, 3.7(1) °, 5.0(1) °, and 9.9(1) °, whichwere measured using X-ray diffraction. We used a high-power
density MPCVD where the microwave plasma was reflectively
concentrated above the diamond substrates by a sphericalchamber.[2] Hydrogen, methane, and nitrogen gases flowed in the
setup at 500, 0.5, and 0.01 sccm, respectively. The pressure,microwave power, and temperature were set to 30 kPa, 2.1 kW,
and 800 °C, respectively. The thickness and nitrogen density of the
diamond films were measured using secondary ion mass
spectrometry (SIMS). The fluorescence of the NV centers wasmeasured using a home-built confocal microscope.
The growth rate increased from 1.8 μm/h to 5.3 μm/h when ߠ௠௜௦increased from 0.4° to 5.0°, and it was 4.4 μm/h at 9.9°.( Fig.2. (a))
Fig.2. (a)–(b) Dependence of the growth rate andThis was discussed by the relationship between a migration length
NV yield on misorientation angles, respectively. (c)of carbon precursors and a terrace width. With increased ߠ௠௜௦ , theCross-sectional image of the CVD diamond filmusing the confocal microscope. (d) CW-ODMR
NV yield, a fraction of the NV center density in the nitrogen
spectra of the CVD diamond film at different
density, increased from 0.4% to 1.1%. (Fig.2. (b)) Finally, a
positions shown in (c).
diamond film was synthesized for 30 h to obtain a thick diamond2film using the 1 mm diamond substrate with ߠ௠௜௦ =9.9°. Figure 2(c) shows a cross-sectional image of the CVD diamondfilm. Considering the refractive index of diamond (2.41) and immersion oil (1.52) and the numerical aperture (NA) of theobjective lens (1.42), the distance of the detection point moved in the CVD diamond film was 1.71 times the distance theobjective lens moved.[3] Thus, the film thickness was calculated as approximately 70 μm (CVD film thickness seen by an
X-Zscan) × 1.72 � 120 μm. Figure 2(d) shows the CW-ODMR spectra of the film at different positions shown in Fig. 5(g).
Only two CW-ODMR peaks were observed, which confirmed the formation of perfectly aligned NV centers throughout the
thick diamond film. This study is useful to design high-sensitivity diamond films using NV centers.
Acknowledgment This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395. and conducted at(NanofabPF, Tokyo Tech), supported by "Nanotechnology Platform Program" of the Ministry of Education, Culture, Sports,
Science and Technology (MEXT), Japan, Grant Number JPMXP09F-21-IT-014.
Reference [1] T. Miyazaki, et al., Appl. Phys. Lett. 105, 261601 (2014).[2] T. Tsuji, H. Ishiwata, T. Sekiguchi, T. Iwasaki
and M. Hatano, Diam. Relat. Mater. [108840], 108840 (2022). [3] E. E. Diel, J. W. Lichtman and D. S. Richardson, Nat.
Protoc. 15 [9], 2773 (2020).

134Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į2-02

Enhancement of fluorescence collection efficiency using angle-shaped diamonds forcompact magnetic sensor
Yuta Shigenobu1, Yuta Kainuma1, Yuji Hatano1, Takayuki Shibata2
Akimichi Nakazono3, Takeshi Ohshima4, Mutsuko Hatano1,4, Takayuki Iwasaki1
1
Department of Electrical and Electronics Engineering, Tokyo Institute of Technology
DENSO CORPORATION,YAZAKI CORPORATION,

2

3

4

National Institutes for Quantum Science and Technology
shigenobu.y.aa@m.titech.ac.jp

Introduction

Nitrogen-vacancy (NV) centers in diamond work as highly sensitive magnetic field sensors with a wide dynamic range, awide operating temperature range, and the ability to simultaneously measure magnetic field and temperature, which are suitable
for applications of battery monitoring1 and biomedical sensing2. In order to improve the magnetic field sensitivity, it isimportant to develop a method to collect red fluorescence emitted from NV centers in a diamond sensor with high efficiency.
A Compound Parabolic Concentrator (CPC) lens3 has been utilized to increase the collection efficiency. In this study, we
propose a new method, which can be combined with the CPC lens, for the enhancement of the collection efficiency using athree-sided-angle-shaped diamond. We found that the efficiency can be more than doubled with a side angle of 30° or higher.

MethodThe sensor head used in the experiment and simulation model is shown in Fig.1, where the distance (t) between the CPC lensand the Photo Detector (PD) light-receiving surface is variable from 1.75 mm to 11.75 mm. First, we used light path analysis
software (LightTools) to simulate the fluorescence collection efficiency (ȕsim) when the diamond side shaping angle ș wasincreased from 0° to 50° with a step size of 10°. Experimentally, a green laser (wavelength: 532 nm) was irradiated to beperpendicular to the (111) plane of the diamond sensor, and PD current was measured. The diamond sensors used were HPHTgrown Ib (111) substrates (2.0ൈ2.0ൈ0.6 mm3). The NV centers were formed by irradiating with an electron beam with a fluenceof 1.0ൈ1018 cm-2 and subsequentlyannealing at 1000 ႏ for 2 hours. Then, the sidewalls of the samples were angle-polished.

ResultFigure 2(a) shows the simulated ȕsim while changing the side-angle and distance between the CPC lens and light-receiving
surface of PD. ȕsim decreases as increasing the distance. Thus, we investigated the dependence of ȕsim on the grinding angle ata short distance of 1.75 mm. The inset of Fig. 2(a) shows that ȕsim increased in the range from 0° to 20°, while it remained
approximately constant from 20° to 40°. The comparison between 0° and 30° polishing shows the increase in ȕsim by a factor
of about 2. The further increase in the angle above 40° again makes ȕsim higher. Then, we performed the experiments using
two samples of 0° and 30° shaping. Figure2(b) depicts the measured PD current as a function of the green laser power. The
PD current of the 30° polished sample becomes 2.4 times higher compared to the 0° sample, which agrees with the simulation.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.

References[1] Y. Hatano et al., Sci. Rep. 12, 13991 (2022) [2] K. Arai et al, Commun Phys 5, 200 (2022)[3] T. Wolf et al., Phys. Rev. X 5, 041001 (2015).
(a)Fig.1 Sensor head structure(b)

Fig.2 (a) Simulation of ȕsim. depending on the polishing angle and PD
position. (b) Experimentally obtained PD current for the 0° and 30°
samples.

135

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į2-03

Transfer-printing-based integration of SiN grating structure on diamond
toward highly sensitive quantum sensor
Ryota Katsumi1, 2, Takeshi Hizawa1, Akihiro Kuwahata2, 3, Shun Naruse1, Yuji Hatano4, Takayuki Iwasaki4,
Mutsuko Hatano4, Fedor Jelezko5, Shinobu Onoda6, Takeshi Ohshima6, Masaki Sekino2, and Takashi Yatsui1, 2
1

Graduate School of Engineering, Toyohashi University of Technology
2
Graduate School of Engineering, The University of Tokyo
3
Graduate School of Engineering, Tohoku University
4
School of Engineering, Tokyo Institute of Technology
5Institute of Quantum Optics, Ulm University
6
National Institutes for Quantum Science and Technology
katsumi.ryota.ti@tut.jp

Introduction

A nitrogen-vacancy (NV) center in diamond is one of the promising candidates for quantum sensing, especially sensitive
magnetic sensing thanks to their excellent spin property1,2. However, their demonstrated magnetic field sensitivity is far
beyond that based on conventional magnetometers including superconducting quantum-interference devices. One of thecritical issues is the poor extraction efficiency of the emitted photons from the diamond NV substrate3. This can be overcome
by implementing the nanostructure on diamond including gratings, but the fabrication of such structure on diamond has thetechnical difficulty.

Method and Result

In this work, we demonstrate the hybrid integration of a silicon nitride (SiN) circular grating structure on a single-crystal
diamond NV substrate toward sensitive magnetometers. Figure 1(a) displays an SEM image of the grating based on SiN,
which is transparent for the NV emission wavelength of ~700 nm. To pick them up, we employed the air-bridged structure
for the grating. By using the pick-and-place transfer printing4 [Fig. 1(b)], the SiN grating was integrated on the diamond NV
substrate. Figure 1(c) displays an optical microscope image of the fabricated device. The SiN grating is bonded with the
diamond NV substrate.
The fabricated device was characterized using micro-SKRWROXPLQHVFHQFH ȝ3/ VSHFWURVFRS\7KH19FHQWHUVZHUHH[FLWHG
with a 532 nm-CW laser. The red curve in Fig. 1(d VKRZVD3/VSHFWUXPPHDVXUHGIRUWKHsample with the SiN grating at
DQLQSXWODVHUSRZHURIP:)RUFRPSDULVRQZHPHDVXUHGWKH3/VSHFWUXPIRUWKHEDUHUHJLRQRIWKHGLDPRQG19
substrate near the SiN grating (blue curve in Fig. 1(d)). The collected photon counts are increased by a factor of up to 1.6
with the SiN grating structure. We also evaluated the magnetic sensitivity of the fabricated device. Figure 1(e) shows thelock-in voltage detected by the lock-in detection system2 as a function of the magnetic field strength B. The detected voltages
with the grating are higher than those in the bare region, which is consistent with the results of Fig. 1(d) and demonstrating
the improvement of the magnetic sensitivity in the fabricated device.
Acknowledgement
This work was supported by MEXT Q/($3*UDQW
1XPEHU
-30;6 and Kakenhi(+ + .
.+DQG.).
References
J. M. Taylor, et al., 1DW3K\V4
 
2
A. Kuwahata, et al., Sci Rep 10
(2020).
3'/H6DJHet al., 3K\VLFDO5HYLHZ%
85, 121202 (2012).
4
R. Katsumi, et al., Optica 5  
1),* D 6(0LPDJHRIWKHIDEULFDWHG6L1JUDWLQJ E 6FKHPDWLFVRIWUDQVIHUSULQWLQJ
of SiN grating on diamond. (c) Optical microscope image of the fabricated device. (d)0HDVXUHG3/VSHFWUD UHGSiN JUDWLQJEOXHEDUHUHJLRQ (e) /RFN-in voltage detectedby the lock-in detection system as a function of magnetic field strength (B).

136

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į2-04

NVC-SPM System to Inspect Electric Devices
Teruo Kohashi1, Masanari Koguchi1, Akehito Shiotake2 and Satoshi Ono2
Hitachi, Ltd., Research & Development Group, Hatoyama, Saitama, 350-0395 JapanThe Graduate School of Informatics and Engineering, The University of Electro-Communications, Choufu,
Tokyo, 182-8585, Japan1

2

teruo.kohashi.fc@hitachi.com

Introduction

A scanning probe microscope using nitrogen-vacancy color centers in diamond (NVC) as a probe (NVC-SPM) has
been developed [1,2], taking advantage of excellent characteristics of NVC, such as high sensitivity for magnetic field
detection in three dimensions and high spatial resolutions. For now, this technique is mainly used to study fundamental
physical phenomena. On the other hand, we are developing an NVC-SPM to inspect electric devices by evaluating
magnetic fields generated from a tiny electric wiring. In this paper, we report the development of a new system including
a compact microwave antenna and mini-mirror, which makes it possible to inspect the predetermined electric circuit in awide circuit board.
Results

It is important to set the microwave antenna as close as fifty Pm to the probe in NVC-SPM, referring to the previously
published example [2]. In order to detect magnetic field generated around a minute wiring between the pads, themicrowave antenna should be inserted between the two electrical pads, which are positioned in the distance of less than
1mm. Moreover, irradiation and detection light are performed with a confocal microscope with a working distance of 4.5
mm. It means that the antenna and the probe should be set above the predetermined electric circuit in the space of 4.5mm.
We need to set these components precisely in the measurement; therefore, it is desired to confirm the position of eachcomponent in the vertical direction from the sample surface. However, the field of view is very narrow through theobjective lens (e.g., several hundred Pm) because the lens center diameter is very small. A new function for precise
position adjustment among these components was required in our SPM system.
Our new NVC-SPM is summarized in Fig. 1. We designed the microwave antenna with very tiny coil with diameter of
500Pm, and mini-mirror to confirm the position of each component from vertical direction using a camera. We developed
the above-mentioned system as shown in Fig. 2, and confirmed that this system works properly. As a next challenge, wewill inspect the actual electric circuit using this NVC-SPM system.


FIG. 1. Newly developed NVC-SPM system with mini-mirror.
FIG. 2 3D-CAD image of set up around the sample.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.

Reference[1] J. M. Taylor, P. Cappellaro, L. Childress, L. Jiang, D. Budker, P. R. Hemmer, A. Yacoby, R. Walsworth, M. D. Lukin,Nat. Phys. 4, 810 (2008).
[2] T. X. Zhou, R. J. Stohr and A. Yacoby, Appl. Phys. Lett 111, 163106(2017).

137

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SE-03A-Į2-05

Enhancing sensitivity with entanglement in coupled nitrogen vacancy centres
Ernst David Herbschleb1, Riku Kawase1, Hiroyuki Kawashima1, Hiromitsu Kato2, Toshiharu
Makino2, Satoshi Yamasaki3, Shinobu Onoda4, Hiroshi Abe4, Takeshi Ohshima4, Norikazu
Mizuochi1
Institute for Chemical Research, Kyoto University
National Institute of Advanced Industrial Science and Technology (AIST)
3
Nanomaterials Research Institute, Kanazawa University
4
National Institutes for Quantum Science and Technology (QST)
herbschleb@dia.kuicr.kyoto-u.ac.jp
12

Introduction

Quantum sensing has great potential for applications that require ultra-high sensitivities. The nitrogen-vacancy (NV)centre is an important example of a quantum sensor, since it works under ambient conditions, enables high spatial resolution,and several physical quantities can be measured. Coherence is a quantum resource that is already utilised in many quantum
sensing protocols. However, the ultimate quantum resource, entanglement, has yet to see use. This could enhance thesensitivity significantly, but it is far from straightforward.

MethodIn our research, to create NV centres that have a high chance to be coupled, we implant molecules with multiple nitrogenatoms into diamond samples, such that the distance between potential NV centres is dictated by straggling only [1]. By
choosing phosphorus-doped diamond ([P] § 5 x 1015 cm-3, created via CVD with enriched 12C [2]), we expect to have ahigher yield [3], and hence a higher chance to find NV centres with a strong coupling. Moreover, the coherence time ispotentially longer [3], which is important for various quantum protocols.
We compare results between intrinsic diamond and phosphorus-doped diamond, for which initial results show an increasein yield (Fig. 1). Moreover, the number of spots with more than one NV centre is consistent with the yield per nitrogen atom;
an example ODMR spectrum is shown in Fig. 1. Double electron-election resonance experiments give the coupling strength
between NV centres, which needs to be sufficiently strong to attempt to utilise a couple for enhanced sensing.

FIG. 1. (Left) Confocal microscope image for intrinsic diamond, showing less than 10 spots with NV centres. (Middle)
Confocal microscope image for phosphorus-doped diamond implanted with the same parameters as intrinsic diamond. There
are over 20 spots with NV centres. Moreover, the photon count per NV centre is higher compared to the intrinsic sample.
(Right) Optically detected magnetic resonance (ODMR) image for a spot with two NV centres with a different orientation.

Acknowledgement
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.
References

Haruyama et al., Nature Communications 10, 2664 (2019).
E. D. Herbschleb et al., Nature Communications 10, 3766 (2019).
3
A. Watanabe et al., Carbon 178, 294-300 (2021).
1
2

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Frequency-bin generation of entangled photons via quantum optical synthesis
Takeru Naito1, Masahiro Yabuno2, Fumihiro China2, Shigehito Miki2, Hirotaka Terai2,
and Ryosuke Shimizu1

The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, Japan
Advanced ICT Research Institute, National Institute of Information and Communication Technology, 588-2
Iwaoka, Nishi-ku, Kobe Japan
n2133076@uec.ac.jp
12

Introduction

Entangled photons in high-dimensional Hilbert space are expected to increase information capacity. Although there areseveral approaches to realize such a high-dimensional state of the entangled photons, frequency-bin encoding is suitable for
optical-fiber-based communication systems with wavelength multiplexing technologies. Up to now, frequency-bin state
generation has been reported in some physical systems; Micro-ring resonators [1] and domain structure engineering of quasiphase-matched devices [2]. However, most of the physical characteristics of the frequency-bin state are determined by thedesigned device structures. Therefore, it may be difficult to precisely adjust the frequency-bin state to the communication
system. On the other hand, we reported manipulating the time-domain structure of a biphoton wave packet via Fourier opticalsynthesis in the frequency domain and realized an ultrafast time-bin state of the biphoton wave packet in several pico-second
ranges [3]. Since the Fourier optical approach is independent of the device structure, it would provide better flexibility inmanipulating the time-frequency structure of the biphoton wave packet. In this study, we present a proof-of-concept
experiment of a two-photon spectral modulation with Fourier optical synthesis (FOS) toward the frequency-bin state
generation with high flexibility.

Experimental results

In this experiment, photon pairs are generated by spontaneous parametric down-conversion using a periodically poled
MgO-doped stoichiometric LiTaO3 (PPMgSLT) crystal. In the earlier experiment with the PPMgSLT, broadband joint
spectral intensity (JSI) distribution with negative correlation was reported even under a type-II phase-matching condition.
Based on this scheme, we develop a spectral manipulation technique by Fourier optical synthesis in the time domain. Since
discrete joint temporal intensity (JTI) distributions are needed for our synthesis, we adopt a bidirectional pumping scheme
to the PPMgSLT crystal by reflecting the pump pulse by a concave mirror. As a result, a sequential JTI distribution withpositive temporal correlation is created. For further manipulation, we placed a dichroic mirror between the PPMgSLT andthe concave mirror to separate the biphoton wave packet, created by the first pumping, from the pump pulse. Adjusting amirror position for the biphoton wave packet, we can control the temporal separation of the two biphoton wave packets alonganti-diagonal direction. Photon pairs from the bidirectional pumped source were collected into a polarization-maintaining
fiber and were sent to a fiber-based spectrometer. We reconstructed JSIs from the arrival time of photons after passing
through the spectrometer. Photons were detected by superconducting single-photon detectors.
Figure 1 represents the resultant JSI when the two JTIs are
distributed parallel to each other to the diagonal direction(a)(b)
defined by ȟ߬௦ ൌ െȟ‫ݐ‬௜ . We can see the JSI is modulated alongઢࣇെઢ࣎െ
the anti-diagonal direction defined by ȟߥ௦ ൌ െȟߥ௜ and it
forms a frequency-bin state. The product of these modulation
periods of each bin and interval of the two JTI is ȟ ି ‫ ڄ‬ȟߥି ؆ͳǤ͵ǡ meaning successful demonstration of the FOS in the time
domain.

Acknowledgement

FIG.1. (a)Expected JTI (b) Measured JSI formed the frequency-bin state.

This work was supported by MEXT Q-LEAP Grant Number JPMXS011806924.

Reference[1] C. Joshi, A. Farsi, A. Dutt, B.Y.Kim, X. Ji, Y. Zhao, A.M. Bishop, M. Lipson, and A.L. Gaeta, “Frequency-Domain Quantum
Interference with Correlated Photons from an Integrated Microresonator,” Phys. Rev. Lett. 124, 143601/1-7 (2020).
[2] C.L. Morrison, F. Graffitti, P. Barrow, A. Pickston, J. Ho,and A. Fedrizzi, “Frequency-bin entanglement from domain-engineered
down-conversion” APL Photonics 7, 066102 (2022).
[3] R.B. Jin, K. Tazawa, N. Asamura, M. Yabuno, S. Miki, F. China, H. Terai, K. Minoshima, and R. Shimizu, “Quantum opticalsynthesis in 2D time-frequency space,” APL Photonics 6, 086104/1-7 (2021).

139Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Į2-07

Development of highly sensitive gravimeter based on atom interferometry using
hybrid system for field applications
Takeshi Hojo, Kaito Takamura, and Ken’ichi Nakagawa
Institute for Laser Science
University of Electro-Communication
t_houjo@ils.uec.ac.jp

Introduction
Transportable gravimeters with the sensitivity of about few micro
Gal (10-9 g) are required in the fields of geophysics and geodesy. As theatom gravimeters have favorable features for these fields such as highsensitivity and no moving elements, they will contribute to these fields.
We have developed a transportable gravimeter for these fields. Our
experimental setup is shown in Fig.1. In our experiment, using retroreflected three-beam MOT, about ͳͲ଻ laser cooled 87Rb atoms areloaded in a glass cell. One of problems to limit the sensitivity of theatom gravimeters is the vibrational noise from the floor through theretro-reflecting mirror of Raman beams (Fig. 1). Therefore, the low
frequency (< 10 Hz) vibrational noise of the mirror should be
suppressed by using passive or active vibrational systems to achieve thetarget sensitivity of the gravity measurement. In our gravimeter system,
we use a commercial passive isolation system with a resonancefrequency of about 0.5 Hz, and we can improve the signal to noise ratioof the interference fringe (Fig, 2). Without a vibrational isolator, we
could not clearly observe the interference signal for the interaction time
longer than 30 ms. By employing a vibrational isolator, we could
FIG 1. Experimental setup.
observe the interference signal for the interaction time up to 45 ms, andthe sensitivity of ȟ݃Ȁ݃ ൌ ͹Ǥʹ ൈ ͳͲି଼ was
realized. However, a residual vibrational noise
limits the sensitivity and we could not further
improve the sensitivity. To improve the sensitivity
further, we consider a hybrid approach in which
both the atom gravimeter and the mechanicalaccelerometer are employed to improve thesensitivity [1]. To realize this hybrid system, wefirst examined the correlation between the signals
from the atom gravimeter and the mechanicalaccelerometer. The phase shift of the observed
interference signal and the shift estimated from the
FIG 2. Interference signals without(red) and with vibrational
accelerometer are plotted in Fig. 3, and we could
isolation(blue)
observe the correlation between both signals. Using
the high correlation between both signals, the phaseof the interference signal is compensated by thephase shift estimated from the mechanicalaccelerometer signal, and we will be able to further
improve the sensitivity of the gravity measurement.

Acknowledgement

This work was supported by MEXT Q-LEAP
Grant Number JPMXS0118069452

Reference[1] Aopeng Xu, “vibration compensation of an atom
gravimeter”, Chinese Optics Letters Vol. 17, Issue
7, 070201(2019)

FIG3. Phase shifts of the interference signal (blue) and theaccelerometer (orange)140

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SE-03A-ȕ2-01

Implementation of Double Quantum Magnetometry to Continuously Excited
Ramsey Method
Yuta Araki1, Ikuya Fujisaki1, Yuji Hatano1, Takeharu Sekiguchi1, Takayuki Shibata2,
Takayuki Iwasaki and Mutsuko Hatano1

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2
DENSO Corporationaraki.y.aj@m.titech.ac.jp

1

Introduction
NV centers, spin qubits in diamond, have been studied for magnetic sensing applications. The continuously excited (CE)Ramsey method reported high sensitivity of 17pT/ξHz for DC magnetometry1. However, for the measurement ofmagneto-encephalo-graphy (MEG) in humans, which is our measurement target, further improvement in sensitivity is needed.
The double quantum magnetometry (DQ) is a method to improve the DC field sensitivity2. Applying DQ to the conventionalRamsey measurement not only effectively doubles the NV gyromagnetic ratio, but also improves T2* due to common-mode
noise rejection. We report the development of a measurement protocol in which DQ is applied to the CE-Ramsey method toimprove the sensitivity of the DC magnetic field.

MethodThe diamond sample was 110-m-thick 12C CVD layer deposited on a type ჟa substrate, and was irradiated with electron
beams of 5 × 1017 cm–2 and annealed. P1 and NV center concentrations were estimated to be approximately 8 ppm and 0.8
ppm. The static magnetic field of 10 mT was aligned parallel to the NV axis. A 532 nm laser was irradiated from the side of
the sample. The fluorescence was focused by a CPC lens and read by a photodetector. To implement DQ, we applied the
MW frequencies resonant to the low-frequency ݉௦ = 0 ՞ െ1 transition and the high-frequency mୱ = 0 ՞ +1
transition simultaneously. The single-quantum (SQ) Rabi frequencies for the two transitions were matched.
ResultCE-SQ-2-Ramsey and CE-DQ-4-Ramsey were performed to confirm the effect of DQ in the CE protocol. Compared to
SQ, twice the frequency of oscillation was obtained in DQ [see Fig.1 (a)], confirming that a doubling of the NV gyromagnetic
ratio was achieved. Dephasing time T2*, fitted values, were similar for SQ and DQ, confirming that common-mode noise
rejection was achieved [see Fig.1 (a)]. Next, to confirm the effect of DQ on sensitivity enhancement, we compared themeasurements of sweeping of detuning, which corresponds to an external magnetic field, between SQ and DQ. The results
confirmed that the slope was improved by the application of DQ [see Fig.1 (b)].










FIG. 1. (a) Comparisons of NV Ramsey measurements (Upper) and Discrete Fourier transform (Lower). (b)Comparisons of
Detuning sweep measurements of SQ and DQ (Upper) and their calculated Slopes (Lower).
Acknowledgements
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.
We thank Dr. Hiromitsu Kato (AIST) and Dr. Shinobu Onoda, Dr. Takeshi Ohshima (QST) for supplying diamond samples.
Reference
C. Zhang, et alPhys Rev Appl, 15, 1 (2021)
2
E. Bauch et al., Phys Rev X , 8, 31025 (2018)
1141

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

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Development of highly sensitive compact quantum sensor with NV center in
12
C-enriched CVD diamond for bio-medical and industrial application

1

Yuta Kainuma1, Yuta Shigenobu1, Yuji Hatano1, Takayuki Shibata2, Akimitchi Nakazono3,
Hiromitsu Kato4, Takeshi Ohshima5, Takayuki Iwasaki1, and Mutsuko Hatano1,5

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2
DENSO CORPORATION
3YAZAKI CORPORATION
4
National Institute of Advanced Industrial Science and technology
5
National Institutes for Quantum Science and Technology
kainuma.y.aa@m.titech.ac.jp

Introduction

Magnetometers based on the ensemble nitrogen-vacancy (NV) centers have high magnetic sensitivity and have monitored
not only rat’s cardiac magnetism1 but also battery current over a wide dynamic range2. For these applications, especially,magnetoencephalography have required high magnetic sensitivity and multiple sensors. Thus, the development of a compact
quantum sensor is important to be implemented in the system with sufficient spatial resolution. However, these sensors havenot achieved the magnetic sensitivity required to detect magnetoencephalography.
We investigated the magnetic sensitivity of the quantum sensor head by lateral laser irradiation using 12C-enriched chemical
vapor deposition (CVD) growth diamond, which is suitable for NV centers and scalable device fabrication.

MethodFigure 1(a) shows the construction of the quantum sensor head, the inside of the dashed line is an NV diamond; The NV
centers in 12C-enriched CVD diamond were formed by electron-beam irradiation (5.01017 e/cm2) and high-temperatureannealing after it. The excitation green laser (wavelength: 532 nm) was focused on the side of the NV diamond by a lens
(focal length: 200mm). The photoluminescence from the NV center collected by compound parabolic concentrator (CPC)
lens and split laser by the beamsplitter in the optical line are detected by a photodiode (PD1) and PD2 as shown in Fig.1(a).
A laser-noise compensation is performed by an auto-balance (AB) circuit and the output signal is modulated by a lock-in
amplifier (LIA) with the modulation frequency (fmod) = 7.03 kHz. The magnetic field was adjusted to be parallel to the NV
quantum axis. The resonance frequency of the lock-in optically detected magnetic resonance (ODMR) spectra was locked
by the output microwave frequency updated. The optical setup was assembled in the magnetic shield.

Result and discussion

The measured signal spectra are shown in Fig.1(b). the floor noise of on- and off-resonance was estimated less than 60
pT/Hz0.5 and 40 pT/Hz0.5, however, electronic noise matched the off-resonance noise at 1 Hz. We confirmed that floor-noise
attenuation in the on-resonance spectra at low frequencies seems that the feedback circuit captures the resonance frequency
of ODMR. From the long-measured magnetic signal, the minimum detectable magnetic field (MDMF) was extracted with
Allan variance, reaching approximately 260 fT. MDMF can be improved by faster feedback circuit and NV diamond quality;
the use of preferentially-aligned NV center CVD diamond improves the magnetic field sensitivity by a factor of about 3 ormore3.
Acknowledgments This work was supported in part by MEXT Q-LEAP Grant Number JPMXS0118067395.
References [1] K. Arai et al., Commun. Phys. 5, 200 (2022), [2] Y. Hatano et al., Sci. Rep. 12, 13991 (2022),[3] C. Osterkamp et al., Sci. Rep. 9, 5786 (2019)

Fig .1 (a)A schematic of the construction of quantum sensor head: dashed line indicates NV diamond sensor. The diamond
was glued to the apex of the CPC lens by optical adhesives. (b) Measured FFT spectrum of magnetic sensitivity. The offresonance was measured with a microwave (fmw = 2.0 GHz) applied. Electronic noise was measured without a laser.

142

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-ȕ2-03

Development of a Nonmagnetic Helical Sensor Drive Multipoint Measuring
Mechanism for Magnetocardiography in Animals
Wenyu Shang1, Motofumi Fushimi1, Shinichi Chikaki1, Masaki Sekino1
1

Graduate School of Engineering, The University of Tokyo
Shangwenyu720@g.ecc.u-tokyo.ac.jp

Introduction

In the clinic, electrocardiography (ECG) and magnetocardiography (MCG) are widely known as common techniques toobserve the electrophysiological activity of the heart. Because the magnetic permeability is more uniform than the
conductivity in the organism, to obtain more accurate cardiac electrical information, MCG usually shows higher accuracy
and specificity than ECG. (for some diseases) [1]. This study will focus on MCG technology. By introducing a new type ofhelical nonmagnetic measurement device, taking animals as the measurement target, we can obtain all-around magnetic field
information to complete the depth measurement of the cardiac current source and realize 3D reconstruction.[2]Methods

In this study, we proposed a new sensor array for MCG measurement in animal to obtain more depth information about
current sources. Unlike conventional devices, we used a ring-shaped sensor array instead of a flat plane sensor array. We
designed a mechanism to realize multipoint MCG measurement and assembled it with nonmagnetic material, as shown in
Figure 1. With this mechanism, MCG data were measured using 3 OPMs.


Figure 1. Multipoint MCG measurement mechanism
Figure 2. Result of MCG measurement in rat
Results and discussion
Figure 2 shows the results of MCG measurement. 3 OPMs with six channels were used to measure the rat's MCG. The twochannels of OPM respectively detected the r and ș direction of ring. The result of additive averaging based on thesimultaneously acquired ECGs shows that the R wave can be clearly captured from directions other than the anterior chestplane. However, its signal strength is weak (about 2 pT), and the design of the mechanism needs to be improved to obtain asignal with a higher signal-to-noise ratio.

Acknowledgments
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.

Reference[1] Shin, et al. (2019). Clinical Hemorheology and Microcirculation, 73(2), 283-291.

[2] R. Fenici, Expert Rev. Mol. Diagn., vol. 5, no. 3, pp. 291–313, May 2005.


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Ensemble NV- center in diamond for quantum sensing created by high fluenceelectron beam irradiation
Shuya Ishii1,2, Seiichi Saiki1, Shinobu Onoda1,2, Yuta Masuyama1, Hiroshi Abe1,2, Takeshi Ohshima1,2
1

Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology, 1233 Watanuki,
Takasaki, Gunma 370-1292, Japan, 2Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 49-1 Ana-gawa, Inage-ku, Chiba 263-8555, Japan

Introduction

ISHII.shuya@qst.go.jp

NV- center has been paid attention as a quantum sensor for highly sensitive detection of magnetic field, electric field,
temperature and strain, etc. [1]. Electron beam irradiation followed by subsequent thermal annealing is known as the effective
procedures to create NV- center in diamond. The electron irradiation generates vacancies in diamond and the annealing
enables vacancies to diffuse in the lattice. Then diffused vacancies are captured by nitrogen atoms, and as a result, NV centers
are created. In addition, substitutional nitrogen atom at a lattice site (P1 center) also acts as a donor for NV center, the charge
state of NV centers changes from neutral (NV0) to NV-. Creation high concentration of ensemble NV- centers is needed toachieve high sensitively sensing [1]. The magnetic sensitivity is proportional to the reciprocal of the number of NV centers
and T2 (spin coherence time), i.e., high concentration NV- centers with long T2 increase the sensitivity. P1 center has animportant role for being a component of NV- centers and acting as donor to the NV center. But it also plays a role asdecoherence source (decrease in magnetic field sensitivity) [1]. Therefore, it is important to create high concentration of NVcenters considering the amount of P1 centers.
In current study, we investigate irradiation fluence dependence of the creation behavior of NV centers in type-Ib diamonds
by using electron spin resonance (ESR) and photo-luminescence (PL) to understand the creation mechanism of NV- center.
The values of T2 are also evaluated by Hahn-echo measurement, since it is one of the key parameters for highly sensitive
magnetometry [1]. Then, we discuss the creation mechanism of NV centers based on concentrations of defects.

MethodThe commercial diamonds synthesized by High Pressure and High Temperature (HPHT) were used. The initial P1
concentrations ([P1]initial) for the samples were measured by ESR, 80, 72, 52, and 46 ppm, respectively. 2 MeV electrons
were irradiated with fluences up to 8.0 ×1018 cm-2 at room temperature. Then, the samples were annealed at 1000ႏ for 2
hours to create NV centers. The concentration of P1 (number of electron spins) was measured by ESR. The initialconcentration of P1 was in the range from 50 ppm to 100 ppm. The ratio of NV- to NV0 was evaluated from PL spectrum.
All these measurements were performed at room temperature. The values of T2 of NV- center ensembles were measured
using a home-built fluorescent microscope with a microwave system.
Results & Discussion
We studied the creation behavior of NV center in type-Ib diamonds with high [P1]initial under relatively high irradiation
fluences. The decrease rate of P1 centers as a function of irradiation fluence shows similar tendencies for all type-Ib diamondsamples, regardless of the initial P1 concentration in the low fluence range (~ 4.0 x 1018 e/cm2). The reduction rate of P1
centers suggests that P1 centers are consumed by recombination with introduced vacancies. However, the decrease rate of
P1 became lower in the high fluence ranges from 6.0 x 1018 e/cm2 to 8.0 x 1018 e/cm2, especially when [P1]initial is smaller,in spite that [P1] still exists even after irradiation at 8.0 x 1018 e/cm2. The process of P1 center consumption seems to shiftdepending on the residual P1 centers. Furthermore, the P1 center consumption and NV- center creation were compared andas a result, it is concluded that some amounts of the P1 centers were consumed by other defects. The conversion efficiency
from [P1]initial to the [NV-] reached ~19% at 8.0 x 1018 e/cm2 and the value confirms the usefulness of electron beamirradiation for high concentration of NV- centers in type-Ib diamonds, whereas results in this study suggests that not all P1
centers converted to NV- center and the residual defects might leads to a cause of decoherence..
Acknowledgement
This work was supported by Quantum Leap Flagship Program (Q-LEAP; JPMXS 0118067395 and
JPMXS0118068379) of MEXT.
Reference[1] J. F. Barry, J. M. Schloss, E. Bauch, M. J. Turner, C. A. Hart, L. M. Pham and R. L. Walsworth. Rev. Mod. Phys., 92,
No.1, 015004 (2020)

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SE-03A-ȕ2-05

Synthesis of n-type diamond using tert-butyl phosphine
for high sensitivity of the NV sensor
Riku Kawase1, Hiroyuki Kawashima1, 2, Hiromitsu Kato2, Norio Tokuda3, Satoshi Yamasaki3,
Mikihiro Kubota1, Masahiko Ogura2, Toshiharu Makino2, Norikazu Mizuochi1, 4Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
3
Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192,Japan
kawase.riku.87n@st.kyoto-u.ac.jp
12

Introduction

Recently, ultra-long spin coherence time (T2 § 2.4 ms) of the single nitrogen-vacancy (NV) center in P-doped n-type
diamond was obtained1. The spin coherence time was the longest in room-temperature among solid-state systems. In
addition to the long T2, as a negative charge state of the NV center is stable2. Furthermore, it also reported that creation
yield of shallow NV centers formed by ion-implantation was improved in addition to longer T2 and improved charge
stability3. Due to such reports, P-doping methods for n-type diamond synthesis is getting more important.
Phosphine is usually used for P-doped diamond synthesis by chemical vapor deposition (CVD). However, phosphine
has high explosibility and toxicity, so it threatens safety of experimenters and expensive exclusion equipment was required.
Therefore, we synthesized P-doped n-type diamond with tert-butyl phosphine (TBP) whose explosibility and toxicity
were lower than phosphine's ones4, and we confirmed that the synthesized sample shows relatively long T2 (1620 ± 100
ȝs, FIG. 1). We also confirmed perfect alignment of NV axis which is also important for high sensitivity of NV quantum
sensor.

FIG. 1. Result of Hahn-echo measurement

Reference

E. D. Herbschleb, H. Kato, Y. Maruyama, T. Danjo, T. Makino, S. Yamasaki, I. Ohki, K. Hayashi, H. Morishita, M.
Fujiwara, N. Mizuochi, Nature Communications, 10, 3766 (2019).
2
Y. Doi, T. Fukui, H. Kato, T. Makino, S. Yamasaki, T. Tashima, H. Morishita, S. Miwa, F. Jelezko, Y. Suzuki, N. Mizuochi,
Physical Review B, 93, 081203(R) (2016).
3
A. Watanabe, T. Nishikawa, H. Kato, M. Fujie, M. Fujiwara, T. Makino, S. Yamasaki, E. D. Herbschleb, N. Mizuochi,
Carbon, 178, 294-300 (2021).
4
H. Kato, S. Yamasaki, and H. Okushi, phys. stat. sol. (a) 202, 2122–2128 (2005).
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395
1



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Decoherence Phenomena in Nitrogen-Vacancy Diamond
Aulden Jones1, Tokuyuki Teraji2, Chikara Shinei2, and Yuta Masuyama3

School of Physics, Georgia Institute of Technology
Research Center for Functional Materials, National Institute for Materials Science3
National Institutes for Quantum and Radiological Science and Technology
12Introduction
Nitrogen vacancy (NV) centers in diamond are atom-sized spin defects whose unique properties enable their use as
robust quantum sensors. Recent research efforts have focused on NV magnetometry, where both single andensemble NVs are used for highly sensitive magnetic field detection with nanoscale spatial resolution. While NV
sensors have been successfully applied to fields ranging from neuroscience to condensed matter physics, ensemble
NV diamonds are still below the sensitivity threshold needed for many more potential applications1. Presented here
is an attempt to investigate the relationship between large crystallographic strain features and the spin coherencetime ܶଶ‫ כ‬in NV-diamonds grown by chemical vapor deposition (CVD). A better understanding of this relationship can
provide valuable input for improving diamond growth methods and eventually extending ܶଶ‫ כ‬.
*This work was supported under the NSF Global Quantum Leap Program under Grant No. OISE-2020174.

Reference

1
J. F. Barry, J. M. Schloss, E. Bauch, M. J. Turner, C. A. Hart, L. M. Pham, and R. L. Walsworth, Rev. Mod. Phys. 92,
015004 (2020).

146Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ2-01

Improvement in the long-term stability of the interferometer gyroscopeusing slow and continuous atomic beams
Naoki Nishimura1, Takuya Kawasaki2, Tomoya Sato2, Ryotaro Inoue2, Mikio Kozuma1,2
1

Introduction

Department of Physics, School of Science, Tokyo Institute of Technology
2Institute of Innovative Research, Tokyo Institute of Technology
nishimura.n.ae@m.titech.ac.jp

Gyroscopes consisting of an atom interferometer can measure angular velocity. Since their expected sensitivity is higher
than that of optical interferometers [1], many studies have paid much attention to the application of atom gyroscopes, forexample, precision measurement of physical constants [2] and inertial navigation of ships and aircraft [3]. We are developing
a matter-wave gyroscope using Raman transitions for a cold and continuous Rb atomic beam. A deadtime-free measurement
and long-stability obtained by a continuous atom beam interferometer benefit the non-GPS type of inertial navigation. In ourprevious study, we successfully measured the rotation of the Earth with our gyroscope with continuous and cold atomic
beam of Rb [4]. Currently, we are aiming to improve the accuracy of the gyroscope for the level required for inertial
navigation.


MethodIn the atom interferometer using Raman transitions, three pairs of counter-propagating Raman beams construct a ʌ/2-ʌ-ʌ/2
Mach-Zehnder type interferometer [5]. The phase in the interference signal, which reflects the Sagnac effect, is measured as
the population ratio between the ground-state hyperfine states F=1 and F=2 of 87Rb atom. The constant frequency shift ο݂in the ʌ Raman beams induces a sinusoidal change in the ratio of the population with the frequency of 2ο݂. We create areference signal of the frequency 2ο݂ based on the signal of the frequency ο݂ by a synthesizer. We estimate the phase of
the fluorescence signal by the lock-in detection with the reference signal.
If drift occurs in the relative phase of Raman beams, it worsens the long-term stability of the interferometer. To eliminate
the spurious phase shift caused by the drift in the relative phase of Raman beams, a simultaneous measurement ofinterferometers with counter-propagating atomic beams that share Raman beams is employed. The sign of the Sagnac phaseshift induced by the rotation depends on the velocity vector, while that induced by other drifts such as acceleration, movementof optical elements, and imperfections in the equipment is the same for the interferometers. Thus, the common-mode phasedrifts are canceled by taking the difference between the output phase shifts in two interferometers while enhancing the phaseshift originating from the system’s rotation. Although the common-mode rejection is a powerful method to improve longterm stability, the common-mode rejection ratio is limited in the actual system. It is desirable to suppress the relative phasedrift itself as much as possible. One of the most significant sources of long-term drift in the output phase of our interferometeris the imperfectness in the relative phase locking of Raman beams. The relative phase of counter-propagating Raman beams
is measured as the optical beat note between Raman beams. The locking of the relative phase is achieved by stabilizing thebeat note to the external RF reference using the PID feedback loop. The performance of the feedback circuit, which consistsof discrete electronic components, is vulnerable to changes in operational conditions, such as temperature. We newly
introduce the feedback circuit consisting of a field programmable gate array (FPGA). The full-digitalized feedback systemis free from the instability stemming from the change in the environmental conditions where the gyroscope is operated. As
a result, the performance of the stabilization of the relative phase of Raman beams is improved.

ResultThe stability of the interferometer as a gyroscope is evaluated by calculating the Allan deviation of the output phase of theinterferometer. The performance of the gyroscope with FPGA-based stabilization for the relative phase of Raman beams will
be reported. In addition, the changes in the response of the interferometer to the variations in the environmental condition
will be presented.

Reference

T. L. Gustavson, P. Bouyer, and M. A. Kasevich, Phys. Rev. Lett, 78, 2046 (1997)
G. Rosi, F. Sorrentino, L. C Acciapuoti, M. P Revedelli, G. M. Tino. Nature, 510, 518-521 (2014)
3
J.C. Fang and J. Qin Sensors, 12, 6331-6346 (2012)
4
T. Sato, R. Inoue and M. Kozuma, short presentation in 4th IFQMS, SE-03A-Ɂ1-05, 7-9 Dec. 2021
5
M. Kasevich and S. Chu, Phys. Rev. Lett, 67, 181 (1991).
1
2

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Bragg interferometer using slow and continuous atomic beamwith sub-recoil transverse momentum width
Tomoya Sato1, Toshiyuki Hosoya2,3, Ryotaro Inoue1 and Mikio Kozuma1,3
Institute of Innovative Research, Tokyo Institute of Technology
2
Japan Aviation Electronics Industry, Ltd.
3
Department of Physics, School of Science, Tokyo Institute of Technology
sato@qnav.iir.titech.ac.jp
1

Introduction

A gyroscope based on interferometry using a continuous atomic beam is one of the most promising candidates for nextgeneration inertial navigation to complement navigation with external references such as GPS because of their highsensitivity, deadtime-free detection, and long-term stability. In recent years, alkaline earth-like atoms have attracted attention
to improving the sensitivity and stability of interferometers [1]. In contrast to alkali atoms, which are widely used in atominterferometry [2], alkaline earth-like atoms do not possess electron spin in their ground state, making them less susceptible
to effects of environmental magnetic fields. An interferometer with Bragg diffraction, which uses only the ground state, canbenefit from this advantage. In addition, higher-order Bragg diffraction increases the area of the interferometer, thus thesensitivity of the gyroscope will be improved.
In atomic interferometry with Bragg diffraction, the interference signal is evaluated by measuring the number of atoms in
different momentum states of the same internal state. Therefore, an atomic beam whose initial momentum width is narrower
than the recoil momentum of the Bragg beam is essential for high-precision measurement. In our recent paper, we propose
a new technique to obtain the high-flux atomic beam of ytterbium (Yb) with sub-recoil momentum width [3]. Theinterferometer with such type of atomic beam will pave the way to the high-end gyroscope for inertial navigation.

MethodBy applying two-dimensional cooling using 1S0-3P1 intercombination transition to a slow atomic beam of 171Yb produced
by dipolar-allowed transition, we have successfully compressed the transverse momentum width of the atomic beam to below
4԰݇, where ԰݇ is the recoil momentum of the Bragg beam (dipolar-allowed 1S0-1P1 transition). For further reduction of
momentum width, we applied a momentum filtering technique to our atomic beam using an ultra-narrow transition between
the ground state and long-lived metastable state 3P2. The atomic beam orthogonally passes the laser light resonant on theultra-narrow transition (507nm). With our experimental condition, the spectral linewidth associated with the transverse
momentum width of the atomic beam is determined by the transit time broadening rather than the lifetime of the metastablestate. Since the transition time broadening is adjusted to correspond to the momentum width of less than ԰݇, atoms can be
excited to the metastable state in a momentum-selective manner. After blowing up the remaining atoms in the ground state,
which have unwanted momentum components, one can obtain ground state atoms within the narrow momentum width bytransporting the atoms from the metastable state to the ground state in the same momentum-selective manner.
The momentum-filtered atomic beam is introduced into the interferometer region, where three pairs of counterpropagating Bragg beams construct the ʌ/2-ʌ-ʌ/2 Mach-Zehnder type interferometer. The Sagnac effect causes the sinusoidal
variation between populations of momentum states 0԰݇ and 2݊԰݇ as a function of the acceleration and angular velocity
on the Sagnac loop, where ݊ is the order of the Bragg diffraction. For the momentum-resolved detection, the third 507nm
light, tuned to excite the 2݊԰݇ state, is introduced just after the interferometer. The change in the population of the 2݊԰݇
momentum state can be detected as the change in the loss of the atoms in the ground state.
Results

We successfully generate an atomic beam of 171Yb whose momentum width is 0.20ሺ8ሻ԰݇ by the momentum filtering.
The higher order Bragg diffraction, up to the 10th, is observed. With the obtained atomic beam with narrow momentum width,
the construction of the Bragg interferometer is ongoing. The present status of the development will be reported.

This work was supported by JST-Mirai Program, Grant Number JPMJMI17A3 and COI-NEXT, Grant Number
JPMJPF2015.

Reference

T. Mazzoni et al., Phys. Rev. A, 92, 053619 (2015).
D. Sayoie et al., Sci. Adv. 4, eaau7945 (2018).
3
T. Hosoya et al., Opt. Commun., 528, 129048 (2023).
1
2

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SE-03A-Ȗ2-03

Development of a cryogenic suspension system for TOrsion-Bar Antennae(TOBA)
Ching Pin Ooi1, Satoru Takano1, Yuka Oshima1, Kentaro Komori2, Yuta Michimura2,3 and Masaki
Ando1,2
Department of Physics, The University of Tokyo
2
RESCEU, The University of Tokyo
3
LIGO Laboratory, California Institute of Technology
ooichingpin@g.ecc.u-tokyo.ac.jp
1

Introduction

TOrsion-Bar Antennae (TOBA), is a proposed gravitational wave antenna1, targeted at observing intermediate mass blackhole mergers with peak sensitivity in the range 0.1 – 10 Hz, but can also be used for early earthquake warnings via measuringtransient gravitational perturbations2. TOBA phase III is currently being built, with a target sensitivity that would make it
useful for early earthquake warnings. To that end, a cryogenic suspension system is being developed to achieve the low
thermal suspension noise requirements. TOBA, as its name suggests, uses torsion bars for sensing. Thus, this work focuseson quantifying and reducing suspension thermal noise of torsion pendulums, with two key technologies, cryogenic
temperatures and crystalline fibres.


MethodOur setup consists of a copper beryllium torsion pendulum, suspended by a 1 mm thick sapphire fibre, and is cooled in acryogenic chamber to near 4 K. The Q value, a parameter which characterizes the thermal noise of the suspension, ismeasured off the setup via an optical lever. Coil-coil actuators were used to excite the torsion pendulum to start off the
ringdown for Q value measurements.

4YV7HPSIRUVDSSKLUH
&RROGRZQ

4:DUPXS


















7HPS .

Fig. 2. Range of Q values with temperature of the cryogenic chamber.
This ranges from 3000 – 70 000 across the temperatures, and we notehere that the highest values are when it is coldest.
Fig. 1. Torsion pendulum suspended by 1 mm 
sapphire fibre, in a cryogenic chamber. Coil-coilactuators provide the initial excitation for ringdown.


Acknowledgments

We would like to thank the Shigemi Otsuka and Togo Shimozawa for manufacturing the mechanical parts used.
This work is supported by MEXT Q-LEAP Grant Number JPMXS0118070351.

Reference

M. Ando et al., Phys. Rev. Lett., 105, 161101 (2010)
J. Harms et al., Geophys. J. Int., 201, 1416-1425 (2015)

1
2

149

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ2-04
Torsion-Bar Antenna for Early Earthquake Alert
Yuka Oshima1, Satoru Takano1, Ching Pin Ooi1,

Kentaro Komori2, Yuta Michimura2,3, and Masaki Ando1,2
1

Department of Physics, University of Tokyo
2

3

RESCEU, University of Tokyo

LIGO Laboratory, California Institute of Technology
yuka.oshima@phys.s.u-tokyo.ac.jp

Introduction

Torsion-Bar Antenna (TOBA) is a highly sensitive gravity gradient sensor using torsion pendulums [1]. We use test
masses suspended horizontally and aim to detect the torsional rotation caused by tidal forces as shown in FIG. 1. The resonant
frequency of torsional motion is ~1 mHz, therefore TOBA has good design sensitivity in low frequencies (0.1 ̽ 10 Hz).
TOBA is useful for gravity-based earthquake early warning [2], and the observation of Newtonian noise and gravitational
waves. A prototype detector Phase-III TOBA with a 35 cm-scale pendulum is under development [3]. The target sensitivity
is set to 10-15 /¥Hz at 0.1 Hz. Phase-III TOBA can detect earthquakes with a magnitude 7 or larger within 10 seconds froma 100 km distance [3].

MethodFor Phase-III TOBA, we operate torsion pendulums at cryogenic temperatures to reduce thermal noise. We havesuccessfully demonstrated cooling down test masses at 6 K [4]. Now, torsion pendulums are under development to achieve
our target sensitivity. Differential Fabry-Perot cavities are used to read out the rotational angle to the pendulums. We finisheddesigning the parameters of Fabry-Perot cavities and the mechanical parts for the pendulums.

FIG. 1. the schematic of TOBA. Test masses are suspended horizontally in the x-y plane and a suspension wire is stretchedin the z-axis. Grey lines represent tidal forces, red arrows show the rotational motion of the pendulums.

Acknowledgments

We would like to thank Shigemi Otsuka and Togo Shimozawa for manufacturing the mechanical parts used. This work
was supported by MEXT Quantum LEAP Flagship Program (MEXT Q-LEAP) Grant Number JPMXS0118070351. Y.O.
was supported by JSPS KAKENHI Grant Number JP22J21087 and JSR Fellowship, the University of Tokyo.

Reference

M. Ando et al., Phys. Rev. Lett., 105, 161101 (2010).
J. Harms et al., Geophys. J. Int., 201, 1416 (2015).
3
T. Shimoda et al., International Journal of Modern Physics D, 29, 1940003 (2020).
4
T. Shimoda, PhD thesis, The University of Tokyo (2019).
1
2

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Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03A-Ȗ2-05
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151

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SE-03A-Ȗ2-06

Experimental generalized measurement of qubits using a quantum computer
Tingrui DONG1,2, Binho LE3, Fumihiro KANEDA1, Soyoung BAEK1 and Keiichi EDAMATSU1
1
Research Institute of Electrical Communication, Tohoku University
2
School of Engineering, Tohoku University
3
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University
dong.tingrui.r7@dc.tohoku.ac.jp

Introduction

Quantum computers, which provide the ability to surpass classical computers, are also able to carry out some fundamental
experiments in quantum mechanics. For example, generalized quantum measurement protocols and their uncertainty
relations1 [1] can be realized and tested in a quantum computer. Here, we propose the implementation of generalized quantum
measurement of qubits in a noisy intermediate-scale quantum computer (NISQ). First, we demonstrate the variable-strength
measurement of a single qubit, which was once studied by photon polarization qubits2, using an NISQ (IBM-Q). The
performance of the measurement is quantified and discussed in terms of the characteristics of the noise and error of the NISQ.
We also implement the nonlocal, variable strength parity measurement of a pair of qubits we recently proposed3. The circuit
we build will also be a part of deterministic, complete Bell state measurement with arbitrary precision. To date, we made ademonstration of the strongest measurement situation by using the 7-qubit quantum computer (ibm-perth). The performanceof the measurement strategy is limited due to the noise and error in present NISQ.
This work is supported by MEXT Q-LEAP (JPMXS0118067581) and JST, the establishment of university fellowships
towards the creation of science technology innovation (JPMJFS2102).
Figures
Fig.1 The measurement circuit of measuring a pair of qubits. The qubit 0 and 1 perform as meter 1 for measurement parity
information. The qubit 2 and 3 perform the entangled system. The qubit 4 and 5 perform as the other meter for checking thephase information. The system pair is coupled with two meters by CNOT gate. Finally, the Bell-state measurement are doneon the system qubits, and the meters are projected on the calculational basis.

Reference

M. Ozawa, Phys. Rev. A, 67, 042105 (2003).
F. Kaneda, S.-Y. Baek, M. Ozawa, and K. Edamatsu, Phy. Rev. Lett. 112, 020402 (2014).
3
P. Vidil and K. Edamatsu, New J. Phys. 23, 043004 (2021).

1
2

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Joint Program Session with Quantum Innovation 2022
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153

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)
Quantum Sensing Track : Short Presentations by Young Researchers
SE-03B. Short Presentations by Young Researchers on SE-01, 04, 06, 07 Topics [5th IFQMS]*Note: Depending on the program, the order of presentations may change within the same group
All the times in the program are Japan Standard time (GMT+9)
Nov 29 (Tue.)

13:10-14:30

14:50-16:10

Session / Presentation

Mentor Chair Co-chair /Presenter

Affiliation

Abstract ID

SE-03B-α1. Break-out Session 1
Chair

Noriaki Yahata

QST

Co-chair

Hidetoshi Kono

QST

Structural dynamics of the Mn4CaO5 cluster during the S2-S3 transition inphotosystem II

Hongiie Li

Okayama U

SE-03B-α1-01

Visualization of hydrogen in Photosystem II by high-resolution Cryo-EM
analysis

Fusamichi Akita

Okayama U

SE-03B-α1-02

Pulsed-EPR study for radical reactions with biological anitioxidants utilizing
quantum effect of electron spin

Hiroki Hirano

Kanagawa U

SE-03B-α1-03

Coherent control of radical pair by local optimization theory

Akihiro Tateno

Saitama U

SE-03B-α1-04

Probing the coherent spin dynamics of radical pairs in weak magnetic fieldusing nanoseconds field switching technique

Ryusei Nozawa

Saitama U

SE-03B-α1-05

Role of a tyrosine radical in the photoreaction of chicken Cryptochrome 4, aHiroaki Otsuka
magnetoreceptor candidate molecule

Waseda U

SE-03B-α1-06

Cavity ring-down measurements by continuous pulse trains for magnetic
field effects on transient radical species.

Tsubasa Kimura

Saitama U

SE-03B-α1-07

Germanium vacancy defects in detonation nanodiamonds for temperaturesensing

Fu Haining

Kyoto U

SE-03B-α1-08

Evaluation of the surface-modified nanodiamond probes by in vivo
fluorescence imaging

Koki Okamoto

Tokyo Tech

SE-03B-α1-09

Detection of heat generation from biological system using double quantum
Hitoshi Ishiwata
thermometry

QST

SE-03B-α1-10

The Anomalous Formation of Irradiation Induced Nitrogen-Vacancy Centers
Frederick Tze Kit SO
in 5-Nanometer-Sized Detonation Nanodiamonds

Kyoto U

SE-03B-α1-11

Microwave antenna architecture for quantitative prediction of ODMR
signals

Keisuke Oshimi

Okayama U

SE-03B-α1-12

Chair

Yoichi Takakusagi

QST

Co-chairRyoko Araki

QST

SE-03B-α2. Break-out Session 1

An Artificial Intelligence Nanopore Platform Detects Omicron SARS-CoV-2 inKaoru Murakami
clinical samples

Hokkaido U

SE-03B-α2-01

Non-equilibrium phi4 theory in a Hierarchy:
Towards Manipulating Holograms in Quantum Brain Dynamics

Kobe U

SE-03B-α2-02

Construction of dipeptide-based DNP-NMR molecular probe library focusing
Yuki Aketa
on kidney injury mouse model

U TokyoSE-03B-α2-03

Nuclear hyperpolarization of liquid water by using photoexcited triplet
electrons in organic nanocrystals

Naoto Matsumoto

Kyushu U

SE-03B-α2-04

Development of Polarizing Agent with Controlled Electronic Structure forHighly Efficient triplet-DNP

Keita Sakamoto

Kyushu U

SE-03B-α2-05

DNP-NMR molecular probe for the detection of Dipeptidyl peptidase-4
activity in vivo

Akihito Goto

U TokyoSE-03B-α2-06

Generation of polarized triplet electron spins at solid-liquid interfaces

Reiya Yabuki

Kyushu U

SE-03B-α2-07

Photoreaction study of a primate blue-light sensitive photoreceptor using
vibrational spectroscopy

Yosuke Mizuno

Nagoya Tech

SE-03B-α2-08

Novel photoisomerization reaction in near-infrared light absorbing
enzymerhodopsins

Masahiro Sugiura

Nagoya Tech

SE-03B-α2-09

Development of a real-time 4D quantum temperature imaging system tomeasure intercellular thermal diffusivity

Haruka Maeoka

Hiroshima U

SE-03B-α2-10

Bidirectional neural network and its application to image denoising, superresolution, and image completion

Kei Majima

QST

SE-03B-α2-11

Molecular insight into photoactivation mechanism of BLUF protein by
QM/MM free energy simulation

Masahiko Taguchi

QST

SE-03B-α2-12

Akihiro Nishiyama154Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-01

Structural dynamics of the Mn4CaO5 cluster during the S2-S3 transition inphotosystem II
Hongjie Li1, Yoshiki Nakajima1, Daichi Yamada2, Kana Hashimoto1, Minoru Kubo2,3, So Iwata3,4,Michihiro Suga1 and Jian-Ren Shen1
1

Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology,
Okayama University, Okayama, Japan
2
Graduate School of Science, University of Hyogo, Hyogo, Japan,
3
RIKEN SPring-8 Center, Hyogo, Japan
4
Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan

Introduction

Photosystem II (PSII) catalyzes light-induced water oxidation through the Si-state cycle at its oxygen-evolving catalyst, a
Mn4CaO5 cluster. During this process, four electrons and four protons are released from two water molecules, and one dioxygen molecule is evolved. Pump-probe time-resolved serial femtosecond crystallography (TR-SFX) has been used tocapture several intermediate states of PSII, deepening our understanding of the water oxidation reaction. Significantly, a
newly inserted oxygen O6 was observed in the vicinity of O5 in the S3-state before the di-oxygen formation1,2. However, theorigin of the O6 and the mechanism to incorporate it remain to be elucidated. To address this issue, we analyzed the structuraldynamics of PSII during the onset of S2-S3 state transition at various time points from nanoseconds to milliseconds after two
flashes (2F) illumination using an X-ray free electron laser at SACLA, Japan.
Following the 2nd flash, no difference electron densities was observed within 20 ns. Instead, from 200 ns to 30 µs, paired
positive and negative difference densities appeared in the area around Q165 and YZ, which was decreased at 200 µs andvanished at 5 ms following the 2nd flash (Fig. 1). Refined models demonstrate that Q165 and YZ move in the same direction
during 200 ns to 30 µs and restore by 5 ms. These movements can be explained by the oxidation and re-reduction of YZ
during the S2-S3 state transition.
One positive density close to the Ca2+ ion, constructed with a water molecule and designated as O6*, appeared during 1µs to 200 µs and vanished at 5 ms, with the concomitant increase of the O6 density from 30 µs to 5 ms (Fig. 1). We speculatethat this water is the origin of O6 and is translocated via the Ca2+ ion binding site to the O6 site. Following the insertion of
O6, Mn4 and Mn1 move apart from each other, opening the Mn4CaO5 cluster and presumably preparing for subsequent dioxygen release in the next state transition.
These results provide important insights into the molecular mechanism of water oxidation in PSII.

Fig. 1. Structural dynamics around the Mn4CaO5 cluster during the S2-S3 transitions. Refined structures are superposedwith Fobs (2F) – Fobs (1F) difference density maps contoured at +3.5 (green) and -3.5 (orange) from 20 ns to 5 ms. The 1F
structure is in grey and the 2F intermediate structure is colored. Black dot lines depict hydrogen bonds. Black arrows
represent structural changes.

Reference

Suga, M. et al., Nature 543, 131-135 (2017)
Suga, M. et al., Science 366, 334-338 (2019)

1
2

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SE-03B-α1-02
Visualization of hydrogen atoms in Photosystem II by high-resolution Cryo-EM analysis
Fusamichi Akita1, Radostin Danev2,3, Yoshiki Nakajima1, Huaxin Yu4, Koji Kato5, Naoyuki
Miyazaki6, and Jian-Ren Shen1
1

Research Institute for interdisciplinary Science, Okayama University
2
Graduate School of Medicine, The University of Tokyo
3
PRESTO, Japan Science and Technology Agency
4
Microbial Sciences Institute, Department of Microbial Pathogenesis, Yale University
5
Structural Biology Division, Japan Synchrotron Radiation Research Institute6
Osaka Research Center for Drug Discovery, Otsuka Pharmaceutical Co., Ltd.
fusamichi_a@okayama-u.ac.jp

Introduction

Photosystem II (PSII) is a membrane protein supercomplex and functions to catalyze light-induced watersplitting, leading to the generation of electrons, protons, and molecular oxygen. PSII consists of 20 protein
subunits and several cofactors, chlorophylls, carotenoids, and the oxygen-evolving center (OEC) responsible
for splitting water through five intermediate states, S0, S1, S2, S3, and S4. The structure of PSII at 1.9 Å
resolution was solved in 2011, which revealed that the OEC has a “distorted chair” shape with a Mn4CaO5composition1. The structure of PSII without radiation damage at the S1 state was determined at 1.95 Å
resolution using femtosecond X-ray free electron lasers (XFEL)2. Subsequently, the S3 state was analyzed using
a time-resolved serial XFEL3, and the structural transition from S2 to S3 was determined using fixed-target
XFEL4. These studies showed the insertion of an oxygen atom (O6) into the vicinity of O5 in the Mn 4CaO5cluster, giving rise to a mechanism of O-O bond formation between O5 and O6. However, there has been little
discussion on the protonation states of residues and water molecules as well as hydrogen release pathways,
which require high-resolution structural analysis. Recent innovations in cryo-electron microscopy (Cryo-EM)
technology have made it possible to achieve high resolutions that may show hydrogen atoms. Here, we
analyzed the structure of PSII at 1.45 Å resolution using Cryo-EM. The difference map obtained showed peaks
arising from hydrogen atoms around amino acid residues and water molecules. In this presentation, I will
discuss the structural analysis of PSII by high-resolution cryo-EM, the protonation states of OEC and thehydrogen atom network.
Fig. The Cryo-EM map of PSII at 1.45 Å resolution. The blue andgreen maps indicate the original Cryo-EM map and the calculateddifference map, respectively.
Reference

1.
Umena Y., Kawakami K., Shen J.-R., Kamiya N., Crystal structure ofoxygen-evolving photosystem II at a resolution of 1.9 Å.Nature, 473, 55-60(2011).
2.
Suga M. et al., Native structure of photosystem II at 1.95 Å resolution
viewed by femtosecond X-ray pulses. Nature, 517, 99-103 (2015).
3.
Suga M. et al., Light-induced structural changes and the site of O=O
bond formation in PSII caught by XFEL. Nature, 543, 131-135 (2017).
4.
Suga M.et al., An open-cubane oxyl/oxo mechanism for O=O bondformation in PSII revealed by XFEL.Science, 366, 334-338 (2019).

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SE-03B-α1-03

Pulsed-EPR study for radical reactions with biological antioxidants
utilizing quantum effect of electron spin
Hiroki Hirano1, Kaito Marumo1, Ikuo Nakanishi2, Akio Kawai1,
1Graduated School of Science, Kanagawa university

Institute for Quantum Life Science, Quantum Life and Medial Science Directorate, National
Institutes for Quantum Science and Technology

2

Introductionr201503326@jindai.jp

Radicals are important species that are highly reactive and play an important role in biological reactions. Usually, aging
and disease of living body are caused by radicals. To protect these problems, there are many biological antioxidants in vivo.
The biological antioxidants work to eliminate highly reactive radicals by reacting with them and transform themselves into
stable radical species. A large number of studies have been made to determine radical reaction rate constants of biologicalantioxidants to evaluate radical trapping abilities1. What seems to be lacking, however, is the observation in elementary
reaction process, particularly in reactions with carbon-centered radicals. For understanding of the radical reactions, itis necessary to discuss them in terms of the kinetics of the elementary reaction process observations.
We have been investigating radical addition reaction mechanisms and rate constants by utilizing time-resolved (TR-) EPR
and pulsed-EPR2. These methods can observe elementary reaction process owing to their high time resolutions of several 10~ 100 ns. The radical reaction rate constants are obtained by measuring the electron spin echo (ESE) decay utilizing pulsedEPR. The ESE signal is given by the spin wave packet of radicals that are in coherent state. Therefore, the radicals can beselectively observed. In this study, we aim to investigate radical reactions of biological antioxidants by identifying thereaction product radicals and determine radical rate constant of biological antioxidants utilizing these techniques.

Experimental method

TR-EPR measurement was performed to identify the intermediate radicals formed by radical reactions of antioxidants.
Radical reaction rate constants of antioxidants were determined by ESE decay measurements. The radicals were generated
by photolysis of radical sources such as aromatic ketone compounds. As for the antioxidants, α-tocopherol (α-TocH) and tritert-butylphenol (TTBP) were used.

Results and Discussion

Fig.1 shows the ESE decays of 2-hydroxypropyl (2Hy-Pr) radical under
different α-TocH concentrations. The ESE of the radicals was generated by aconventional Hahn echo pulse sequence with a π/2 pulse and a τ-delayed π pulse,which was initiated at t ns after the laser flash (laser flash – t – π/2 – τ – π – τ –ESE). The decay was obtained by monitoring the ESE signal intensity, S(τ), forseries of τ values. The top line is the ESE decay of the 2Hy-Pr radical without
antioxidants. The ESE decay rate, 1/TM*, was determined by the exponential
decay fitting procedure of the S(τ) profile on the basis of the equation,2𝜏𝜏𝜏𝜏
𝑆𝑆𝑆𝑆(𝜏𝜏𝜏𝜏) = 𝑆𝑆𝑆𝑆0 exp � ∗ �
𝑇𝑇𝑇𝑇𝑀𝑀𝑀𝑀
with S0 (initial ESE amplitude) and TM* as a fitting parameter. Then, the ESE
decay measurements were performed with different concentrations of α-TocH(Fig.1). It was found that the 1/TM* was faster depending on the α-TocHconcentration. This is due to the elimination of 2Hy-Pr by the reaction with αTocH. 1/TM* of these decays were also determined and the results were plottedagainst the concentration of α-TocH (Fig.2). The liner relationship was obtained
and therefore, the radical reaction rate constant, k, was determined by the liner
fitting following the equation,
1
1+ 𝑘𝑘𝑘𝑘 [𝛼𝛼𝛼𝛼-TocH]∗ =𝑇𝑇𝑇𝑇𝑀𝑀𝑀𝑀
𝑇𝑇𝑇𝑇𝑀𝑀𝑀𝑀
where 1/TM is the α-TocH -independent the ESE decay rate. The determined kvalue was (3.2 ± 0.2) ×106 M-1 s-1. At the conference, we will discuss thereactivity of α-TocH by comparing the rate constant of TTBP.

Reference1
2

Fig.1 Time profiles of ESE intensity, S (τ), of 2Hy-Pr
under various α-TocH concentrations.

Fig.2 Stern-Volmer type analysis of 1/TM* of 2Hy-Pr
radical versus [α-TocH].

Packer, J. E., Slater, T. F., and Willson, R. L., Nature, 278, 737–738 (1979)
H. Hirano, H. Takahashi, A. Kawai, J. Phys. Chem. B, 126, 6074-6082. (2022)

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SE-03B-α1-04

Coherent control of radical species by local optimization theory
Akihiro Tateno1, Kenta Masuzawa1, Hiroki Nagashima1, Michihiko Sugawara2, and Kiminori
Maeda1
1

Graduate School of Science and Engineering, Saitama University
2
Keio Quantum Computing Center, Keio University
a.tateno.275@ms.saitama-u.ac.jp

Introduction
Design of laser waveforms optimized for reaction control has attracted theoretical and experimental attention1. However,
it is not easy to realize the designed laser field. In contrast, recent progress of arbitrary wave generator (AWG) enables us
to produce the designed radio wave field (RF). Recently, we have shown that it is possible to control the recombination
reaction of a radical pair (RP) in high field using radio wave magnetic resonance designed based on the local optimization
theory1,2. As an example of coherent control, here we show the spin multiplicity control of RP at low fields and the designof optimized AWG pulse that induce selective spin echoes.
Coherent control in local optimization targets a transient state |𝑓𝑓⟩𝐿𝐿 that is non-eigenstate of the Hamiltonian at a specifictime tf. In order to produce |𝑓𝑓⟩𝐿𝐿 at tf, it is necessary to calculate the moving target |𝜌𝜌𝑓𝑓 ⟩𝐿𝐿 that time-evolves to |𝑓𝑓⟩𝐿𝐿 . |𝜌𝜌𝑓𝑓 ⟩𝐿𝐿
can be calculated by the time reverse Liouville operator as shown by|𝜌𝜌𝑓𝑓 ⟩𝐿𝐿 = 𝑒𝑒𝑒𝑒𝑒𝑒 {𝑖𝑖𝐿𝐿̂ 0 (𝑡𝑡𝑓𝑓 − 𝑡𝑡)} |𝑓𝑓⟩𝐿𝐿

We have chosen the singlet state and the Sy+Sz states as |𝑓𝑓⟩𝐿𝐿 for the reaction control of RPs and the selective spin echomeasurement, respectively.
The calculation for the spin multiplicity control was done in a model RP system having one nuclear spin (HFC A=0.5mT). In low magnetic field, almost all spin states are mixing coherently. We calculated an RF field with the aim ofcontrolling a singlet born RP to singlet state after 1 μs. The FIG.1a shows time-evolutions of the singlet probability inpresence and absence of designed RF field. The RF irradiation change the singlet probability at 1 μs after the productionof RP from 39 % to 96 %.
As a model system for selective control of spin systems, we used a mixed system of TEMPO (solution) and BDPA (solid)
whose stick diagram of the resonance lines is shown in FIG. 1b. In this system, we designed the RF waveform so that theelectron spin of TEMPO radical transitions to the Sy state for three hyperfine lines at t =200 ns keeping the electron spinof BDPA in the Sz state. FIG 1c shows that the calculated RF provides the FT-EPR spectrum of selectively excited TEMPO
radicals (solid line) whereas the spectrum obtained by composite pulse of three colour RF pulses contains the signal ofundesired the other radical (broken line).

(1)

(2)

(3)

FIG. 1) Upper: Calculated RF, Lower: Time-evolution of singlet probability. 2) Model system 3)Calculated spin echo
after optimised pulse(solid line) and after multi-colour pulse(dotted line)

References

M. Sugawara, J. Chem. Phys.118(15). 6784-6800 (2003).
K. Masuzawa, M. Sato, M. Sugawara, and K. Maeda, J. Chem. Phys. 152, 014301 (2020)

1
2

158

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-05

Probing the coherent spin dynamics of radical pairs in weak magnetic fieldusing nanoseconds field switching technique
Ryusei Nozawa1, Taisuke Matuo1, Hiroki Nagashima1, Kiminori Maeda1
1Department of Chemistry, Graduate School of Science and Technology, Saitama University.

r.nozawa.939@ms.saitama-u.ac.jp
Introduction

Recent discussions of the mechanism of magnetic sensitivity in animals have focused attention on the spin dynamics ofradical pairs in the low-field region and the effects of the magnetic field. The existence of low-field effects in radical pairs
is easy to confirm, since the magnetic field effects in radical pairs are in the opposite direction of those in the usual hyperfine
coupling and relaxation mechanisms, but there are many theoretical models that are believed to be responsible for themagnetic field effects.[1] Matsuo et al. used nanosecond magnetic field switching techniques for the xanthone-DABCO
system in SDS micelle solutions to analyze the behavior of radical pairs at weak magnetic fields and found the decay timeof the transient absorption change was extremely short only when the external magnetic field was changed from the peakmagnetic field of the low-field effect to zero field.[2] This result suggests that the origin of the low-field effect in this system
is not pseudo-normal spin mixing, but coherent due to the breaking of the degenerate electron-nuclear spin state. We also
thought we could observe a time equivalent to coherent low-field effect generation by applying nanosecond magnetic fieldswitching techniques. Based on these, the nanosecond magnetic field switching technique was further applied in this study
to four more magnetic fields exhibiting low-field effects to zero field to probe the coherent low-field effect generation process.

Method・・Result

MARY spectra in the low-field region obtained in SDS micellar solutions of xanthone and DABCO are shown in FIG
1[a]. Transient absorption changes associated with magnetic field switching from four low magnetic fields(1.5, 1.1, 0.7, 0.4mT) to zero magnetic field were monitored and their post-laser delay time dependence plotted. Experimental resultson the curve of 𝑡𝑡 ≈ ℎ/2𝑔𝑔𝜇𝜇𝐵𝐵 𝐵𝐵0 as shown FIG1[b]. Comparing this result with the time evolution of the Singlet-likemagnetic field effect by the one-nucleus spin model, it reflects the most prominent time of the coherent onset of the lowfield effect due to the breaking of the degeneracy of the electron-nucleus spin state by the Zeeman energy. This indicatesthat the present method captures the generation of the low-field effect due to the breaking of the degeneracy in time. However,some other systems do not exhibit such ideal behavior and don’t reflect the coherent rise time. This indicates the possibilityof the influence of decoherence of spin systems, mechanisms of low-field effects other than degenerate breaking, and so on.

FIG.1. [a]Experimental results of MARY spectra of the Xanthone-DABCO system and thescheme for changing the magnetic field. [b] Calculation results magnetic field effects of Singlet in
the one-nuclear spin, and the result of inverse field switching.
Reference[1] 1Maeda, K. et al., Nature, 452,387-390(2008).
[2] 1Matuo.T., Master thesis(2018).

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SE-03B-α1-06

Role of a tyrosine radical in the photoreaction ofchicken Cryptochrome 4, a magnetoreceptor candidate molecule
Hiroaki Otsuka1, Ryosuke Miyake1, Keiko Okano1, Yasushi Imamoto2, and Toshiyuki Okano1
1

Department of Electrical Engineering and Bioscience, School of Advanced Science and Engineering,
Waseda University
2
Department of Biophysics, Graduate School of Science, Kyoto University
o1.2t5.8tt21.tf@ruri.waseda.jp

Introduction

Some animals have the ability of magnetoreception [1]. Interestingly, themagnetoreception of birds and insects is driven by light. As a possible mechanism of
the light-dependent magnetoreception, “Radical pair mechanism (RPM)” has been
proposed, in which the magnetosensitive bifurcation of reaction of two entangled
radicals (radical pair) formed by photoexcitation is used [2]. The magnetic sensor in
RPM would have the light-sensitivity and the ability of radical formation, andcryptochromes (CRYs) are considered to be candidates for the magnetoreceptor. Our
previous study revealed the ability of photoreception via flavin adenine dinucleotide
chromophore (FAD) and radical formation of CRY4 in the chick retina [3–5]. The
spectroscopic analysis of the transient reaction of chicken CRY4 (cCRY4) identified
a formation of FAD anion radical (FAD●‒) upon light absorption, which was reacted
into bifurcated reaction of oxidation or protonation. Interestingly, a neutral tyrosine
radical (Tyr-O●) like spectrum was detected with the formation of FAD●‒ and it
decayed along with the protonation of FAD●‒ [6]. According to RPM,
magnetosensitive reaction of bifurcation to reduction and oxidation is expected to a
key step. Although the detail role and the site of Tyr-O● formation are unknown, TyrO● could play an important role in the bifurcation.
In this study, we aim to identify the site of Tyr-O● formation and elucidate the roleof Tyr-O● in the photoreaction of cCRY4 by comparing the photoreaction of cCRY4tyrosine mutant with that of wild-type cCRY4.

MethodTyr319 is an amino acid locating near the fourth tryptophan that constitutes aputative electron-transfer pathway called Trp-tetrad in cCRY4, and it was mutatedto phenylalanine (F). Wild-type and Y319F mutant of recombinant cCRY4 wereexpressed by yeast expression system and purified by GST-tag-based purification
system. Steady-state photoreactions and their efficiencies were analyzed using
double beam spectroscopy (UV-2450). Transient reactions of each sample were
measured by laboratory-built, time-resolved spectrophotometry system.

FIG. 1. Reaction model ofcCRY4 WT and cCRY4 Y319F(A) FAD●‒ binding cCRY4 isbifurcated into oxidation form andprotonation form. Tyr-O● decays as
FAD●‒ oxidizes. (B) Almost FAD●‒
oxidizes in cCRY4 Y319F, and Trp●
is formed instead of Tyr-O●.

Results and discussion
The chromophore FAD in the dark-state of cCRY4 is oxidized (FADOX). Blue light irradiation reduces the FADOX to
FAD●‒, a part of which is immediately (subsecond order) protonated to a neutral radical form (FADH●). Quantum yield of
FADOX → FADH● in cCRY4 WT was 16%, while that in cCRY4 Y319F decreased to 6.0%. As reported previously, cCRY4
WT showed FAD●‒ formation immediately after photoexcitation (< 0.5 ms), followed by bifurcation to fast (≈ 100 ms)
oxidation (FAD●‒ → FADOX) and slow (≈ 400 ms) protonation (FAD●‒ → FADH●), the former of which was accompanied
by decay of Tyr-O● (FIG. 1A). In contrast, most of the FAD●‒ was oxidized in cCRY4 Y319F, and noticeably, spectra
resembling tryptophan neutral radicals (Trp●) instead of Tyr-O● were observed (FIG. 1B).
The observation of Trp●-like spectra in cCRY4 Y319F is consistent with the idea that Tyr319 donates electron to FAD
via Trp tetrad. The suppression of the FAD●‒ protonation in cCRY4 Y319F suggests a possible role of Tyr-O● in the
protonation.
Reference

1R. Wiltschko and W. Wiltschko, Adv. Exp. Med. Biol. 739, 126 (2012); 2T. Ritz, S. Adem, and K. Schulten, Biophys. J. 78, 707 (2000);
3Y. Kubo, M. Akiyama, Y. Fukada, and T. Okano, J. Neurochem. 97, 1155 (2006); 4R. Watari, C. Yamaguchi, W. Zemba, Y. Kubo,

K. Okano, and T. Okano, J. Biol. Chem. 287, 42634 (2012); 5H. Mitsui, T. Maeda, C. Yamaguchi, Y. Tsuji, R. Watari, Y. Kubo, K.
Okano, and T. Okano, Biochemistry 54, 1908 (2015). 6H. Otsuka, H. Mitsui, K. Miura, K. Okano, Y. Imamto, and T. Okano,
Biochemistry 59, 3615 (2020).

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SE-03B-α1-07

Cavity ring-down measurements by continuous pulse trains
for magnetic field effects on transient radical species.
Tsubasa Kimura1 and Kiminori Maeda1
1

Department of Chemistry, Graduated school of Science and Engineering, Saitama University
t.kimura.485@ms.saitama-u.ac.jp

Introduction

The magnetic field effect (MFE) measurements of photo-generated radical pairs in photochemical reactions fundamentallyneed very high sensitivity and long acquisition with many light pulse irradiations. The degradation due to the multiple pumppulse irradiations is a difficult concern when we apply to precious biological samples. Previously, the sensitivity problem
was solved with pump-probe type cavity ringdown (CRDS) method [1], which boosts the effective optical path length using
optical cavity. If we compared the CRDS with the cavity enhanced absorption spectroscopy (CEAS) [2], the CRDS ontransient absorption (TA) measurements has advantageous aspects: 1) free from correction of the wavelength dependent
cavity enhancement, 2) free from the fluctuations of the probe beam, 3) clear estimation of the time resolution.
Here we developed a new CRDS technique named super-CRDS (SCRDS) [3], which is sequential CRDS measurements
using a pulse train of a super continuum source (SC source). SCRDS allows us to measure the absorptions at many delay
times with 200 ns interval (5 MHz). Therefore, we can get the transient absorption (TA) time trace by a single excitation
simultaneously. This fact dramatically reduces the number of excitation light irradiations, keeping the sensitivity as same as
pump-probe CRDS.

MethodThe TA at 500~600 nm and its magnetic field effect were measured by SCRDS technique. The mixed aqueous solution of
FMN 50 μM and HEWL 200 μM, 40 mL was flown from a syringe pump to a sample cell (200 μL volume and 1 mm opticallength). The CRDS signal is penetrated from the back side of the cavity mirror and monitored by a photomultiplier tube. The
CRD signals are fit by a single exponential function for every delay times. The transient absorbances A per single pass ofthe probe light can be calculated by the lifetime of the signal  and that at the negative delay time  The TA was measured
in the field range from 0 to 20 mT. Pulsed magnetic fields, whose duration is 1.8 ms, were synchronized with the excitation
pulse laser. The flat region of the magnetic field in time was used for the TA measurements. In the MFE measurement, theabsorption was measured while the magnetic field was varied by 2 mT, and the absorption from 10 to 90 μs was averaged toobtain the magnetic field effect at each magnetic field. This process was repeated 200 times at each magnetic field.
Results
The intensity of the excitation light was adjusted to be comparable to that of Ref [1]. FIG. 1 is a plot of TA time profiles,
and FIG. 2 is a plot of MFE measurement. SCRDS requires only one-tenth of the number of shots, (200 shots), to measure
the TA for a single magnetic field intensity, and the error can be suppressed to ±0.25 %.

FIG. 1. Time-resolved transient absorption signal
in the system of FMN 50 μM and HEWL 200 μM.
The signal obtained by 100 shots laser excitation isaveraged.

FIG. 2. Magnetic field effect using SCRDS
in the system of FMN 50 μM and HEWL 200 μM.
200 shots averaged per points.

Acknowledgements: This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644

References: [1] Maeda, K et al., J. Am. Chem. Soc., 133, 17807–17815 (2011).
[2] Neil, S. R. T et al. J. Phys. Chem. B, 118, 4177-4184(2014).
[3] Japan Patent 2022- 7803.

161

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-08

Germanium Vacancy Defects in Detonation Nanodiamonds
for Temperature Sensing

Haining Fu1, Masanori Fujiwara1, Izuru Ohki1, Ming Liu2, Akihiko Tsurui2, Taro Yoshikawa2,
Masahiro Nishikawa2, and Norikazu Mizuochi1
1Institute for Chemical Research, Kyoto University
2
Daicel Cooperation
fu.haining.82r@st.kyoto-u.ac.jp

Introduction

Group IV color centers such as silicon-vacancy center (SiV) and germanium-vacancy center (GeV) in nanodiamonds (NDs)
are promising candidates for all-optical nanoscale thermometry. Because these defects have sharp zero phonon lines (ZPLs)
and the ZPL peak wavelength changes depending on local temperature. For live-cell application, NDs should be smaller than
30 nm to avoid non-invasive methods. However, the minimum size of NDs concluding group IV color centers as temperature
sensors reported was 200 nm [1]. This motivated us to synthesize NDs by detonation method, which is suitable for the mass
production of NDs in smaller size. In 2020, we reported the first synthesis of SiV-containing detonation nanodiamonds (SiVDNDs) [2]. Then, we performed all-optical thermometry with SiV-DNDs in an average size of 20 nm. This is the smallest
size applied for thermometry using color-center-containing NDs [3].
Compared to SiV center, GeV center shows higher quantum efficiency, and its ZPL peak wavelength is 100 nm shorter
than SiV center, make it a good candidate for temperature sensing. GeV-containing detonation nanodiamonds (GeV-DNDs)
has been synthesized successfully according to the recent report [4]. And in our current study, we focus on the temperaturesensing of GeV-DNDs, evaluated their PL spectrum response according to temperature. GeV center combining SiV centeris suitable for multi-color imaging application and local temperature measurements of live-cell organelles.
Methods & Results
After the detonation of explosives with Ge dopant, our sample was processed by purification, dispersion, surface
modification, and ultracentrifugation. Supernatant and suspension were collected as different samples. In addition, thesediment was also collected and dispersed into pure water as another sample. Each sample was dropped on a coverslip,
natural drying in the air atmosphere. A thermoplate is set to control the sample temperature. Each sample were observed andtaken photoluminescence (PL) image by a homebuilt confocal microscope.
Both the supernatant and suspension samples showed weak GeV centers’ ZPL signals at around 602 nm, and a strong PL
background signal from DND itself has been observed. In the sediment sample, however, we found a strong ZPL signal fromsome bright spots in PL image (Fig. 1(a)). These bright spots may be GeV-DND aggregations or large GeV-DND particles.
At these spots, we confirmed that the ZPL peak wavelength (λ) linearly red-shifted with increasing temperature (T) (Fig.
1(b)). The slope Δλ/ΔT is an indicator of the temperature response and the average value is 0.009 nm/K, which agrees with
the GeV center ensemble in a bulk diamond (0.008 nm/K) [5]. The particle distribution is investigated by transmission
electron microscope image. The average particle size is 20 nm, much smaller than the reported GeV-NDs for thermometry
application (400 nm) [6]. Finally, we measured and calculated the temperature sensitivity (ηT), which defined as thetemperature deviation (σT) per unit integration time (1s). As an example, a temperature sensitivity as 1.9 K Hz-1/2 measured
at a bright spot shows in Fig. 1(c), means that a sub-Kelvin temperature change can be measured in 10 seconds.
This work is supported by MEXT Q-LEAP (No. JPMXS0120330644).

Figure 1 (a) PL image of the GeV-DND sediment sample. (b) and (c) Temperature dependence and temperature sensitivity
measurements at the bright spot depicted in a white circle in (a).

Reference[1] C. T. Nguyen, et al., Appl. Phys. Lett. 112, 203102 (2018). [2] Y. Makino, et al., Diam. Relat. Mater. 112, 108248 (2021).
[3] M. Fujiwara, et al., Carbon, 198, 57 (2022). [4] Y. Makino, et al., Diam. Relat. Mater. 130, 109493 (2022) [5] S. Blakley,
et al., ACS Photonics, 6,1690 (2019). [6] T. T. Tran, et al., Sci. Adv. 5 eaav9180 (2019)162

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-09

Evaluation of the surface-modified nanodiamond probes
by in vivo fluorescence imaging
Koki Okamoto1, Masaya Muto1, Tetsuya Kadonosono1, Kiichi Kaminaga2, Ryuji Igarashi2, andShinae Kizaka-Kondoh1
12School of Life Science and Technology, Tokyo Institute of Technology
Institute for Quantum Life Science, National Institutes for Quantum Science and Technology
okamoto.k.am@m.titech.ac.jp

Introduction

In recent years, fluorescent nanodiamond have attracted attention as a novel in vivo imaging probe1. Nitrogen-vacancy
centers in nanodiamond have electrons whose quantum state (such as spin resonance frequencies) change according tochanges in the surrounding environment. This variation of quantum state can be used to develop environmentally responsive
sensor probes2, 3. Tumors have a unique and complex microenvironment characterized by hypoxia4, which is closely
associated with treatment resistance and malignant progression, making it important therapeutic targets. Early detection oftumor hypoxia is expected to contribute to the improvement of cancer treatment.
Our goal in this research is to develop nanodiamond imaging probes that can detect hypoxia in tumors with high sensitivity .
Here, we take full advantage of the excellent photostability of fluorescent nanodiamonds, to perform fundamental in vivo
evaluations of 50-100 nm surface-modified diamond nanoparticles, which are the basic for creating hypoxia probes. We
evaluated their fluorescence sensitivity upon in vivo administration (intratumoral, subcutaneous, and intravenous) in mice.
Polyglycerol hydrophilically modified 100-nm nanodiamond particles were found to be the most sensitive for fluorescence
detection among the particles evaluated, and thus will be used as a base material to create sensor probes that detects hypoxic
cells using the cellular oxygen sensor function. Such probes are expected to contribute to early detection of hypoxic diseases
including malignant tumors.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644.

Tables and Figures

FIG. 1. Representative images of mice with hypoxic tumors(top: bioluminescence) and nanodiamond particles injected
into tumor (bottom: fluorescence).

FIG. 2. In vivo fluorescence image of subcutaneously
injected surface-modified nanodiamond particles.

FIG. 3. In vivo fluorescence image of 100-nm nanodiamondparticles with polyglycerol hydrophilic modification at theindicated time points after subcutaneous injection of theparticles.

Reference

M. H. Alkahtani et al., Nanophotonics, 7, 1423-1453 (2018)
M. Fujiwara et al., Sci. Adv., 6, 37 (2020).
3
T. Fujisaku et al., ACS Nano, 13, 11726-11732 (2019)4
V. Petrova et al., Oncogenesis, 7, 10 (2018)
1
2

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Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-10Detection of heat generation from biological systemusing double quantum thermometry
Hitoshi Ishiwata1, Kano Suzuki2, Kiichi Kaminaga1, Takeshi Murata2, Ryuji Igarashi1
1
QST, Institute for Quantum Life Science,2
Graduate School of Science and Membrane
Protein Research and Molecular Chirality Research Centers,
Chiba University
ishiwata.hitoshi@qst.go.jp
Introduction

The NV center in a diamond is a quantum sensor with exceptional quality for highly sensitive thermometry. For
quantification of heat generation from biological system, thermometry technique that allows to quantify accuracy andprecision of temperature is necessary. While many biological applications have been demonstrated by detection of CWODMR spectrum from NV center, it is difficult to quantify accuracy and precision of temperature measurement from peakfitting of CW ODMR spectrum. In this talk, we utilized all three energy levels |0>, |±1> of NV center to perform Double
Quantum Thermometry for highly sensitive and accurate measurement of temperature. Advantage of biological heat
detection using double quantum thermometry will be discussed in the talk.

ResultFIG. 1. Double Quantum thermometry using NV center indiamond.

FIG.1 shows typical result of Double Quantum
Thermometry by Thermal Echo measurement using
NV center in diamond. The energy difference between
the bright |0〉 and dark |± 1〉 states were observed as an
oscillation in the Thermal Echo signal. Inset of Figure
1 shows pulse sequence used for Thermal Echomeasurement.
Change in oscillation frequency of Thermal Echomeasurement was observed for different value ofapplied microwave frequency. As difference between
applied frequency and D(T) changed from 2 MHz, 2.5
MHz, 3 MHz, oscillation was observed at frequency of
2MHz, 2.5MHz, 3MHz respectively. Analysis ofoscillation frequency showed temperature precision of
0.3K, demonstrating sub-degree temperature precision
for measurement of biological temperature.
Application of quantum thermometry with highprecision will be discussed in the talk.

Reference:

This research was supported by MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) Grant Number
JPMXS0120330644.

164Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-115The Anomalous Formation of Irradiation Induced Nitrogen-Vacancy Centersin 5-Nanometer-Sized Detonation Nanodiamonds
Frederick T.-K. So1,2,3, Alexander I. Shames4, Daiki Terada2,3, Takuya Genjo2,3, Hiroki Morishita1,
Izuru Ohki1, Takeshi Ohshima5, Shinobu Onoda5, Hideaki Takashima6, Shigeki Takeuchi6, Norikazu
Mizuochi1, Ryuji Igarashi3,7, Masahiro Shirakawa2,3*, Takuya F. Segawa2,8*1

Institute for Chemical Research, Kyoto University
Department of Molecular Engineering, Graduate School of Engineering, Kyoto University
3
Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology
4
Department of Physics, Ben-Gurion University of the Negev, Israel
5
Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology
6
Department of Electronic Science and Engineering, Kyoto University
7
National Institute for Radiological Sciences, National Institutes for Quantum Science and Technology
8
Laboratory for Solid State Physics, ETH Zurich, Switzerland
so.kit.58a@st.kyoto-u.ac.jp
2

Introduction

Nanodiamonds containing negatively charged nitrogen-vacancy (NV–) centers are versatile room-temperature
quantum sensors in a growing field of research. Yet, knowledge regarding the NV– formation mechanism in very small
particles is still limited. This study focuses on the formation of the smallest NV–-containing diamonds, 5 nm detonation
nanodiamonds (DNDs). As a reliable method to quantify NV– centers in nanodiamonds, half-field signals in electron
paramagnetic resonance (EPR) spectroscopy are recorded. By comparing the NV– concentration with a series of
nanodiamonds from high-pressure high-temperature (HPHT) synthesis (10–100 nm), it is shown that the formation
process in 5 nm DNDs is unique in several aspects. NV– centers in DNDs are already formed at the stage of electron
irradiation, without the need for high-temperature annealing, an effect related to the very small particle size. Also, theNV– concentration (in atomic ratio) in 5 nm DNDs surpasses that of 20 nm-sized nanodiamonds, which contradicts theobservation that the NV– concentration generally increases with particle size. This can be explained by the 10 times
higher concentration of substitutional nitrogen atoms in the studied DNDs ([NS ≈ 1000 ppm]) compared to the HPHT
nanodiamonds ([NS ≈ 100 ppm]). Upon electron irradiation at a fluence of 1.5 × 1019 e–/cm2, DNDs show a 12.5-foldincrement in the NV– concentration with no sign of saturation reaching 1 out of about 80 DNDs containing an NV–
center. These findings can be of interest for the creation of defects in other very small semiconductor nanoparticles
beyond NV-nanodiamonds as quantum sensors.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644 & JPMXS0118067395,
KAKENHI (Grants 20H00453, 18K19297 and 21H04444)

MethodFigure 1. (a) Continuouswave HF EPR spectra (ν =9.87* GHz) of electronirradiated (2 MeV, 5 × 1018
e−/cm2) NDs with different
particle sizes after hightemperature annealing. The
double integral of the signal atgeff = 4.23 provides the NV−
concentration. (b) A summarygraph of NV− content (ppm, inunits of atomic ratio) in NDs of different sizes, measured via the HF EPR technique. Blue bars are the pristine NDs, orange
bars are the electron-irradiated NDs, and yellow bars are the electron-irradiated and subsequently annealed NDs (derived
from the geff = 4.23 signal in the EPR spectrum of panel a). Electron irradiation was conducted with 2 MeV electrons at afluence of 5 × 1018 e−/cm2. Annealing was performed at 800 °C in vacuum for 2 h. All samples were boiling acid treated at
130 °C for 3 days to remove Fe3+ impurities, which overlap with the HF EPR NV− signal. Inset table shows the corresponding
NV− concentrations in ppm. Errors in NV− concentration do not exceed ±15%.

165Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-12
Microwave antenna architecture for quantitative prediction of ODMR signals
Keisuke Oshimi1*, Masazumi Fujiwara1
1

Grad. Sch. Natural Science and Technology, Okayama University*pcfw97je@s.okayama-u.ac.jp

Introduction
Quantum sensing with fluorescent nanodiamonds (NDs) containing nitrogen-vacancy (NV) centers is performed under
the fluorescence microscope with microwave irradiation. It reads a modulation of optically detected magnetic resonance(ODMR) of electron spins of NV centers. This technique and the low cytotoxicity and biocompatibility of NDs enable tomeasure physical quantities inside biological samples, such as electric field, magnetic field, and temperature. So far, several
antenna structures have been developed for microwave excitation and used in biological research [1-3]. Recently, we reported
a glass-based antenna device having millimeter-scale area of microwave irradiation [4]. In this work, we demonstrate thequantitative prediction of the ODMR on our antenna devices, by thoroughly studying the relationship between the antenna
properties and ODMR contrast.
MethodWe quantitatively predict ODMR contrast on the glass surface of the antenna chip device developed for ODMR
measurements in biological samples (FIG. 1(a)). As shown in FIG. 1(b), we first simulated the microwave magnetic field(|B|) in the ODMR measurable area (sample detection area) by numerical simulation based on the finite element method,
considering the microwave reflection and transmission of chip devices and microwave components (cables, RF switches,
and amplifier). We next converted the simulated |B| to ODMR contrast of NDs using a theoretical equation based on
rotational Bloch equations [5]. For the comparison of this theoretical ODMR with the experimental results, we overlaid thetheoretical curve, as shown in FIG. 1(c). We found theoretical results closely matched the experimental results, whichindicates experimental ODMR measurements are predictable by the numerical simulation at the stage of design development.
In the presentation, we explain about the development methodology, and the future biological application of ND-based
quantum sensing.
This work was supported by the Nanotechnology Platform Project (Nanotechnology Open Facilities in Osaka University) of
MEXT (JPMXP09F21OS0055), JSPS-KAKENHI (19K21935, 20H00335, 20KK0317), AMED (JP21zf0127004), JST(JPMJMI21G1), the MEXT-LEADER program, the Mazda Foundation, and Osaka City University Strategic Research Grant
2017–2020, MEXT Quantum Leap Flagship Program (MEXT Q-LEAP, JPMXS0120330644).
(a)

(b)

B [G]

(c)

1.0
0.6
0.4
0.2
0.0

PL [a.u.]

1.00

1 mm
0

|B| [G]

0.8

0.4

0.95
0.90
0.85
0.80
0.75

0

200

400

600

y-coordinate [μm]800FIG. 1 (a) Photograph of an antenna chip device. (b) The computed spatial distribution of |B| at 2.87 GHz on thechip surface. (c) Position dependence of the simulated |B| (top; blue line) and measured ODMR depth (bottom;
black squares) with the line calculated from the simulated |B| (bottom; red line).

Reference
1Yukawa et al., Nanoscale Adv., 2, 1859 (2020). 2J. Choi et al., PNAS, 117, 14636 (2020). 3R. Igarashi et al.,J. Am. Chem. Soc., 142, 7542 (2020). 4 Oshimi, Nishimura, Matsubara, Tanaka, Shikoh, Zhao, Zou, Komatsu,
Ikado, Takezawa, Kage-Nakadai, Izutsu, Yoshizato, Morita, Tokunaga, Yukawa, Baba, Teki and Fujiwara,
Lab Chip, 22, 2519 (2022). 5A. Dréau et al., Phys. Rev. B, 84, 195204 (2011).

166

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SE-03B-α2-01
An Artificial Intelligence Nanopore Platform Detects Omicron SARS-CoV-2 in clinical samples
Kaoru Murakami1,2, Shimpei Kubota1,2, Keiichiro Akabane1, Kumiko Tanaka1, Rigel Suzuki3, Yuta
Shinohara1, Hiroyasu Takei4, Shigeru Hashimoto1, Yuki Tanaka2, Shintaro Hojyo1,2, Kazuki Sato1,6,
Yuichi Kojima1,6, Masateru Taniguchi5*, and Masaaki Murakami1,2,12*

1) Molecular Psychoimmunology, Institute for Genetic Medicine, Graduate School of Medicine, Hokkaido
University, Sapporo 060-0815, Japan
2) Group of Quantum immunology, Institute for Quantum Life Science, National Institute for Quantum andRadiological Science and Technology (QST), Chiba 263-8555, Japan
3) Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo,
060-0815, Japan.
4) Aipore Inc., 26-1 Sakuragaokacho, Shibuya, Tokyo 150-8512, Japan.
5) The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, 567-0047, Osaka, Japan.
6) Department of Hematology, Faculty of Medicine, Hokkaido University, Sapporo, 060-8638, Japan

Abstract
We recently reported a highly accurate, cost-effective artificial intelligence nanopore platform (AInanopore platform) to detect coronaviruses, including Wuhan SARS-CoV-2 within five minutes.
We here show that this platform can further distinguish SARS-CoV-2 alfa, beta, gamma, delta, andomicron variants. Moreover, it identified mutated Wuhan SARS-CoV-2 expressing the spike
proteins of the delta and omicron variants. Furthermore, we identified the omicron variant with asensitivity of 100% and specificity of over 94% in saliva specimens isolated from COVID-19
patients, which is the similar and/or better values to RT-PCR. Importantly, AI-nanopore platform
can identify even low concentrations of omicron variants with both sensitivity and specificity ofover 95% in saliva specimens, which had more than 30 Ct values of RT-PCR analysis and are hard
to be evaluated by RT-PCR, suggesting that the platform has an advantage over RT-PCR analysis.
Thus, this AI-nanopore platform may be an effective diagnostic tool for emerging infectious
pathogens including SARS-CoV-2 in clinical situation.

Rationale:
We recently reported an artificial intelligence (AI)-nanopore platform that enables testing for Wuhan
SARS-CoV-2 with high sensitivity and specificity. However, which parts of SARS-CoV-2, whether
mutated SARS-CoV-2 variants, or clinical samples with low concentration of virus are recognizedby the AI-nanopore platform are unknown.
Objectives:
To investigate these three questions.

167

Methods:

We analyzed cultured SARS-CoV-2 alpha, beta, gamma, delta, and omicron variants using an
improved AI-nanopore platform. To identify the specific SARS-CoV-2 structures detected by theplatform, we prepared mutated Wuhan variant SARS-CoV-2 expressing the spike proteins of the deltaor omicron variants. Additionally, we analyzed 241 saliva samples with omicron variants collectedfrom 132 infected and 109 uninfected people based on RT-PCR results using the platform.
Measurements and Main Results:
The platform distinguished cultured SARS-CoV-2 the five variantsand the mutated Wuhan variant,suggesting the platform’s sensitivity for the spike protein. Furthermore, it identified omicron SARSCoV-2 with a sensitivity of over 100% and specificity of over 94% from saliva specimens isolated
from COVID-19 patients. Moreover, the platform can identify even low concentrations of omicron
variants with both sensitivity and specificity of over 95% in saliva specimens, which are hard to beevaluated by RT-PCR.

Conclusions:
The AI-nanopore platform is an effective diagnostic tool for SARS-CoV-2 variants in clinical samples
even with low concentration virus.
Keywords: COVID-19 diagnosis, AI-nanopore, SARS-CoV-2 variants

168

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-024Non-equilibrium 𝜙𝜙 theory in a Hierarchy:
Towards Manipulating Holograms in Quantum Brain Dynamics
Akihiro Nishiyama1, Shigenori Tanaka1 and Jack A. Tuszynski2

Graduate School of System Informatics, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada T6G 1Z2
1

2

anishiyama@people.kobe-u.ac.jp
Introduction

We describe non-equilibrium 𝜙𝜙 4 theory in a hierarchical manner in order to develop a method for manipulating coherent
fields as a toy model of introducing control into Quantum Field Theory (QFT) of the brain, which is called Quantum Brain
Dynamics (QBD). We begin with the Lagrangian density of 𝜙𝜙 4 model, and derive the Klein--Gordon equation of coherent
fields with a damping term as an input--output equation proposed in areas of morphological computation or reservoir
computing. Our analysis is extended to QFT in a hierarchy representing multiple layers covering cortex in a brain. We findthat the desired target function is achieved via time-evolution in the Klein--Gordon Eqs. in a hierarchy of numericalsimulations when a signal in both the input and output prevails over noise in the intermediate layers. Our approach will beapplied to control coherent fields in the systems (in a hierarchy) described in the QFT framework, with potential applications
allowing to manipulate quantum fields, especially holograms in QBD.

FIG. 1. Quantum field 𝜙𝜙(𝑥𝑥) in a hierarchy.

FIG. 2. Distribution of evolving coherent field 𝜙𝜙(𝑥𝑥).

169

Acknowledgement
The present work was supported also by MEXT Quantum Leap Flagship Program (MEXT QLEAP)
Grant Number JPMXS0120330644.
Reference
1
Akihiro Nishiyama, Shigenori Tanaka, and Jack A. Tuszynski. Non-equilibrium Quantum Brain Dynamics II:
Formulation in 3+1 dimensions. Physica A: Statistical Mechanics and its Applications, 567:125706, 2021.
Akihiro Nishiyama, Shigenori Tanaka, and Jack A. Tuszynski. Quantum Brain Dynamics andHolography. Dynamics 2.2: 187-218, 2022.

2

170

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SE-03B-α2-03

Construction of dipeptide-based DNP-NMR molecular probe library focusing on
kidney injury mouse model1

Yuki Aketa1, Yutaro Saito1, Fuminori Hyodo2, Masayuki Matsuo3 and Shinsuke Sando1,4

Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Japan2
Department of Radiology, Frontier Science for Imaging, School of Medicine, Gifu University, Japan3
Department of Radiology, School of Medicine, Gifu University, Japan
4
Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Japan

Introduction

Dissolution dynamic nuclear polarization (dDNP) is a powerful technique that dramatically enhances the sensitivity ofmolecular probes in nuclear magnetic resonance imaging (NMR/MRI), which allows non-invasive detection of NMR/MRI
signals in a deep site of the body with high sensitivity1,2. Molecular probes hyperpolarized with dDNP have been successfully
applied for metabolic imaging in vivo and have been expected to have medical applications such as disease diagnosis andassessment of drug treatment2,3. Although various DNP-NMR molecular probes have been developed4, a limited number ofbiomarkers, usually well-studied enzymes, have been targeted despite the enormous number of potentially targetable
enzymes expressed in vivo. This situation is mainly due to the paucity of enzymes known to be associated with diseases. In
addition, it is unclear which enzymatic activity is applicable to the diagnosis of diseases by DNP-MRI even if the enzymatic
activity can be detected in the biosamples. To expand the utility of DNP-NMR, it is desired to devise a new approach todiscover biomarker enzymes applicable to the disease diagnosis by DNP-NMR. To this end, we envisioned that it would bean effective strategy to compare the metabolic activity of diseased and healthy tissues for a compound library and discovermolecules with disease-specific activity. We focused on exopeptidase which cleaves N- or C-terminus peptide bonds in
peptides because they are known to be related to disease progression,5-7 and we selected dipeptides for the library because
they could be recognized from two types of exopeptidases, aminopeptidase and carboxypeptidase, at least.
In the present study, we designed dipeptide libraries targeting aminopeptidases and carboxypeptidases respectively andprepared 180 compounds of the dipeptide libraries in total. Finally, we carried out a screening assay with the dipeptide
libraries in the kidney injury mouse model. In this presentation, we will show the design strategy for the dipeptide libraries
and the screening results.

Tables and Figures

Reference

Figure. 1. Strategy for discovering new biomarkers in this study.

J. H. Ardenkjær-Larsen et al., Proc. Natl. Acad. Sci. U. S. A. 100, 10158–10163 (2003).
K. Golman et al., Proc. Natl. Acad. Sci. U. S. A. 103, 11270–11275 (2006).
3
S. E. Day et al., Nat. Med. 13, 1382–1387 (2007).
4
Y. Kondo et al., Angew. Chem. Int. Ed. 60, 2–23 (2021).
5
L. Guzman-Rojas et al., Proc. Natl. Acad. Sci. U. S. A. 109, 1637–1642 (2012).
6
D. A. Silver et al., Clin. Cancer Res. 3, 81–85 (1997).
7
P. Selvakuamar et al., Clin. Cancer Res. 10, 2771–2775 (2004).
1
2This work was supported by MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) Grant Number JPMXS0120330644.

171Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-04

Nuclear hyperpolarization of liquid water by using photoexcited triplet electrons
in organic nanocrystals
Naoto Matsumoto1, Koki Nishimura1, Nobuo Kimizuka1, Yusuke Nishiyama2,3, Kenichiro Tateishi4,
Tomohiro Uesaka4, Nobuhiro Yanai1,51Department of Applied Chemistry, Graduate School of Engineering, Center for Molecular Systems, Kyushu
University,
2
NanoCrystallography Unit, RIKEN-JEOL Collaboration Center, 3JEOL RESONANCE Inc.,
4
Cluster for Pioneering Research, RIKEN, RIKEN Nishina Center for Accelerator-Based Science,
5
FOREST, JSTyanai@mail.cstm.kyushu-u.ac.jp

Introduction

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are powerful methods to analyze molecular
structures and diagnose diseases. However, the sensitivity of NMR/MRI is quite low because of the low nuclear spinpolarization. Dynamic nuclear polarization (DNP) can improve the sensitivity of NMR/MRI by transferring highly polarized
electron spins to nuclear spins. On the other hand, the DNP using radical electrons uses electron polarization in thermal
equilibrium, which requires cryogenic temperatures (~4 K) to obtain high polarization.
Recently, DNP using photoexcited triplet electrons (triplet-DNP) has attracted much attention (FIG. 1).1 In triplet-DNP,
the use of non-equilibrium electron polarization allows nuclear hyperpolarization even at room temperature. However,polarizable targets have been limited to solid samples because polarization transfer from electrons to nuclei requires strong
dipole interactions.2 Towards the biological application, the hyperpolarization of liquid water has remained an important
challenge. In this work, we demonstrated the first hyperpolarization of liquid water by triplet-DNP.3

FIG. 1. Schematic representation of triplet-DNP.

Results and discussion

The hyperpolarization of liquid water in triplet-DNP requires polarization transfer from crystals to water, and it isimportant to increase the surface area of crystals. We prepared 3 sizes of nanocrystals, 390, 270, and 170 nm, respectively,by reprecipitation method and each sample was named NC390, NC270, and NC170, respectively. Triplet-DNP experiments with
mixtures of nanocrystals and water showed 1HNMR signal enhancement not only crystals but
also water (FIG. 2a). 1H-NMR enhancement ofwater was increased by decreasing the size ofnanocrystals, indicating that hyperpolarization ofwater was derived from nanocrystals (FIG. 2b).
Some control experiments and simulations
revealed a scenario of water hyperpolarization inwhich polarization of photoexcited triplet electron
was transferred to nuclear spins in the
FIG. 2. (a) 1H-NMR spectra of thermal (black) and after triplet-DNP
nanocrystals, and then transferred to liquid water for 120 s (green) at 28.2 MHz. (b) Nanocrystal size dependent 1Hat the nanocrystals-water interfaces.
NMR enhancement of water.

Reference

A. Henstra et al., Chem. Phys. Lett., 165, 6 (1990).
K. Nishimura et al., Chem. Commun., 56, 7217 (2020)
3
N. Matsumoto et al., J. Am. Chem. Soc., 144, 18023 (2022)
1
2

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SE-03B-α2-05

Development of Polarizing Agent with Controlled Electronic Structure forHighly Efficient triplet-DNP
Keita Sakamoto1, Tomoyuki Hamachi1, Kenichiro Tateishi2, Tomohiro Uesaka2,
Nobuo Kimizuka1,3, Nobuhiro Yanai1,3,4
1

Department of Applied Chemistry, Graduate School of Engineering, Kyushu University
2

RIKEN Nishina Center for Accelerator-Based Science

3

Center for Molecular Systems (CMS) Kyushu University
4

FOREST, Japan Science and Technology Agency
yanai@mail.cstm.kyushu-u.ac.jp

Introduction
Dynamic nuclear polarization using photo-excited triplet electron (triplet-DNP) achieves the nuclear
hyperpolarization by transferring polarization from triplet electron spins to nuclear spins. However, it hasremained difficult to attain large nuclear polarization in amorphous materials of practical importance. Thisis due to the broadening of ESR spectra of the triplet state by the random orientation of the polarizing
agents and the anisotropic interaction of the electron spins. While the ESR spectra can be sharpened bycontrolling the orientation of the polarizing agents within a single crystal,1,2 the target molecules cannot be
incorporated into the single crystal. Therefore, instead of such “orientation control”, this study aims to
sharpen the ESR spectra and improve the DNP efficiency by "molecular design" focusing on the electronic
structure of polarizing agents.

MethodThe shape of the ESR spectra is determined by the zero-field splitting
parameters (D, E), which reflect the electronic structure of the excited triplet
state. When the electrons are symmetrically delocalized, the values of |D|and |E| become smaller and the ESR spectrum becomes sharper. In order toobtain such delocalized electronic structures, we have synthesized 6,13di(thiophen-2-yl)pentacene) (DTP) by introducing a thienyl group, a fivemembered ring with small steric hindrance, into pentacene, and evaluatedits electronic structure and polarization performance (FIG 1).
FIG. 1 Chemical structures ofTime-resolved ESR measurements of pentacene and DTP were
pentacene and DTP
conducted in a β-estradiol glass matrix. Compared to pentacene, DTP
showed more intense and sharper ESR signal thanks to their smaller |D| and|E| values (FIG. 2a).
The triplet-DNP experiment was
conducted with an integrated solid effectsequence. o-Terphenyl (OTPh) was
employed as the amorphous matrix.
FIG. 2b shows the buildup curve of 1H
NMR signal intensity after triplet DNP
at 120 K. For triplet-DNP with DTP, thefinal polarization after 5 min reached
0.83%, about three times higher thanthat with pentacene. Triplet-DNP ofpartially deuterated OTP ([D14]OTP : FIG. 2 (a) ESR spectra and, (b) buildup curve of 1H NMR signal Intensity.
OTP = 90 : 10 wt% (OTPd)) with DTP
resulted in the polarization of 7.5%,which was much higher than the previous highest value of 1.5%.3
Reference

Takeda. K, Triplet State Dynamic Nuclear Polarization (VDM, Saarbrücken, Germany, 2009).
Tateishi. K, et al., Proc. Natl. Acad. Sci. U. S. A, 111, 7527–7530 (2014).
3
Tateishi. K, et al., Angew. Chem. Int. Ed,52, 13307-13310 (2013).
1
2

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SE-03B-α2-06

DNP-NMR molecular probe for the detection of
Dipeptidyl peptidase-4 activity in vivo

Akihito Goto1, Hiroyuki Yatabe1, Kazutoshi Yamamoto2, Murali C. Krishna2, Yutaro Saito1, andShinsuke Sando1
1

Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo
2
National Institute of Health, USA
goto-akihito0528@g.ecc.u-tokyo.ac.jp

Introduction

Dipeptidyl peptidase-4 (DPP-4) is a peptidase that cleaves peptides at the second residues from the N-terminal terminus,
preferentially when the second residue is proline or alanine (Figure 1). Because DPP-4 is related to various diseases such astype 2 diabetes and cancers, DPP-4 is a potential therapeutic target and biomarker1,2. Thus, the detection of DPP-4 activity
in vivo will be a powerful technique for diagnosis.
Nuclear magnetic resonance imaging (NMR/MRI) is an imaging method that can observe and visualize the dynamics ofmolecular targets deep inside the body at high spatiotemporal resolution. In the medical field, however, the observation
targets are limited to 1H nuclei of water or lipids abundant in the body. This is due to the low sensitivity of NMR. Dynamic
nuclear polarization (DNP) can solve this problem by enhancing NMR sensitivity as much as 103–105 times. DNP is achievedby irradiating microwave to probes in the presence of stable radicals at a cryogenic temperature under high magnetic field totransfer polarization of electron spins to nuclear spins3. DNP-NMR molecular probes are required to satisfy the following
requirements: (1) sufficient length of spin-lattice relaxation time correlated with hyperpolarized lifetime, (2) sufficiently
large chemical shift change to distinguish a molecular probe and a product, (3) fast reaction with targets, and (4) selective
reaction with targets (Figure 2).
In this study, we attempted to develop a DNP-NMR molecular probe for the detection of DPP-4 activity in vivo bydesigning the molecular structure to satisfy these requirements. In the presentation, we will show the design strategy and therecent results.

Tables and Figures

Figure 1. DPP-4 and preferential cleavage site.

References

Figure 2. Requirements for DNP-NMR molecular probes.

C. F. Decon, Front. Endocrinol. 10, 80 (2019).
K. Ohnuma et al., Front. Biosci. 23, 1754–1779 (2018).
3
J. H. Ardenkjaer-Larsen et al., Proc. Natl. Acad. Sci. U. S. A. 100, 10158–10163 (2003).
1
2

This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644
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SE-03B-α2-07

Generation of polarized triplet electron spins at solid-liquid interfaces
Reiya Yabuki1, Tomoyuki Hamachi1, Koki Nishimura1, Kenichiro Tateishi2, Tomohiro Uesaka2 andNobuhiro Yanai1,3,4
1

Department of Applied Chemistry, Graduate School of Engineering, Kyushu University
2

RIKEN Nishina Center for Accelerator-Based Science
3
4

Center for Molecular System, Kyushu University

FOREST, Japan Science and Technology Agency
yanai@mail.cstm.kyushu-u.ac.jp

Introduction
Triplet-DNP can enhance NMR sensitivity at room temperature utilizing the electron polarization of the triplet state 1,2.
However, it has been difficult to enhance the solution NMR signal by triplet-DNP due to the immediate relaxation ofpolarized triplet electron spins in solution. Towards the direct polarization of solution by triplet-DNP, we aim for thegeneration of polarized triplet electron spins at solid-liquid interfaces.

MethodIn this study, we used tetrakis (4-carboxyphenyl) porphyrin (TCPP, FIG.
1a) as a polarization agent and aminopropyl silica gel (ASg, FIG. 1b) as a

(a

(b)

solid support. TCPP-modified ASg was dispersed in toluene. We evaluatedwhether polarized electron spins of triplet states are generated at the solidliquid interface by time-resolved ESR measurements.
Under pulsed laser excitation at 527 nm, ESR spectrum and the peak
decay of TCPP on ASg surface in toluene were measured. The ESR spectrum

FIG. 1. Chemical structures of(a) TCPP and (b) ASg

showed a characteristic line shape of the spin-polarized triplet state of TCPP3(FIG. 2). Furthermore, the lifetime of the spin-polarized state wasapproximately 3.0 μs, which was long enough to carry out the triplet-DNP
measurement. This result indicates that the use of solid support suppressed the
dynamics of the polarization agents and the relaxation of electron spinpolarization at the solid-liquid interface.

Reference

FIG. 2. ESR spectrum of
TCPP-ASg in toluene

W. T. Wenckebach et al., Chem. Phys. Lett., 165, 6-10 (1990)

1

N. Yanai et al., J. Phys. Chem. Lett., 10, 2645-2650 (2021)

2

L. Bolzonello et al., Phys. Chem. Chem. Phys., 19, 27173-27177 (2017)

3175Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-08

Photoreaction study of a primate blue-light sensitive photoreceptor using
vibrational spectroscopy
Yosuke Mizuno1, Kota Katayama1, Hiroo Imai2, and Hideki Kandori1
1

2

Graduate School of Engineering, Nagoya Institute of Technology
Center for the Evolutionary Origins of Human Behavior, Kyoto University
y.mizuno.092@stn.nitech.ac.jp

Introduction

Photoreceptor proteins are expressed in eyes and function as vision systems. There are two types of photoreceptors. One
is rhodopsin which responsible for twilight vision, another one is cone pigments which responsible for color vision. These
proteins commonly bound 11-cis-retinal as a chromophore. Retinal absorb UV light (370 nm) in the solution and absorb
about 440 nm by making Schiff base linkage. Further, protein moiety determines the absorption range from UV to red light1.
The photoreaction mechanisms and structural information were well known in rhodopsin. However, Cone pigment havebeen less known than rhodopsin because of low expression level and handling difficulty. We previously observed the firststructural data of the primary Batho intermediate state of primate red (MR), green (MG) and blue (MB) cone pigments by
low-temperature FTIR spectroscopy 2. Recently, we also reported the structural study of BL intermediate in MB which isformed from initial photointermediate 3. Here, we extended these vibrational structural studies by identifying subsequent
photointermediate of cone pigments, especially MB.
Results
By using low-temperature UV−visible spectroscopy, we found that the Lumi intermediate (223K) of MB formed intransition from the BL intermediate (163K) shows an absorption maximum in the UV region (Fig.1), indicating the
deprotonation of the retinal Schiff base. Comparison of the light-induced difference FTIR spectra of Batho (77K), BL, andLumi showed significant α-helical backbone C=O stretching (1661 and 1652 cm-1) and protonated carboxylate C=O
stretching vibrations (1714 and 1712 cm-1) only in the Lumi intermediate (Fig.2). Thus, the transition from BL to Lumi
involves dramatic changes in protein environment with a proton transfer reaction between the Schiff base and the counterion
resulting in an absorption maximum in the UV region4.

Tables and Figures

FIG.1. UV-visible absorption spectra of MB (left) andlight-induced difference spectra (right) with >430 nm illumination(solid line) and 360 nm illumination (dash line) at 223K

FIG.2. Light-minus-dark difference FTIR spectra of MB at 223, 163,
and 77 K in the 1780−1600 cm−1 region. Spectra were measured in
H2O (black) and D2O (red).

Reference

O.P. Ernst et al., Chem Rev, 114, 126-163 (2014).
K. Katayama et al., Sci Rep, 7, 4904 (2017).
3
S. Hanai et al., Biophys Physicobiol, 18, 40-49 (2021).
4
Mizuno et al., Biochemistry, in press
1
2

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SE-03B-α2-09

Novel photoisomerization reaction innear-infrared light absorbing enzymerhodopsins
Masahiro Sugiura1*, Kazuki Ishikawa1, Kota Katayama1,2, Yuji Sumii1, Rei Abe-Yoshizumi1,
Satoshi P. Tsunoda1,2, Yuji Furutani1,2, Norio Shibata1, Leonid S. Brown3, Hideki Kandori1,2**
1

Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Japan
2
OptoBioTechnology Research Center, Nagoya Institute of Technology, Japan3
Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Canada*: m.sugiura.734@stn.nitech.ac.jp, **: kandori@nitech.ac.jp
Introduction

Rhodopsins is a large family of retinal-binding photoreceptive membraneproteins found in microbes and animals 1. Microbial rhodopsins has different
functional family, including light-driven ion pumps, light-gated ion channels,
light sensors, and light-activated enzymes (FIG.1). Microbial rhodopsins
possess retinal chromophores that capture light energy and isomerize from alltrans to 13-cis (FIG.1). Although this isomerization reaction was universallyconserved in microbial rhodopsins, a recently discovered microbial rhodopsin,
bestrhodopsin, offered surprising photochemical properties.
Bestrhodopsin is a far-red light absorbing novel microbial rhodopsin, in
which one or two rhodopsin domains are fused to a bestrophin channel andfunction as light-gated ion channels 2. The surprises were that bestrhodopsin
performs an all-trans to 11-cis photoisomerization and it show no photoreaction FIG.1 Functions and photoisomerization
at low temperatures at <170K, despite any microbial rhodopsin can react 2.
of microbial rhodopsin
Our target protein is enzymerhodopsin (NeoR) which was reported in 2020 3.
This NeoR is similar to besrhodopsin in the following four points 3. First, it absorbs far-red and near infra-red light. Second,
the rhodopsin domain forms heterodimers. Third, it has eight transmembrane α-helices whereas normal rhodopsin iscomposed of seven transmembrane α-helices. Finally, three carboxylic acids are conserved around the retinal as achromophore, different from normal microbial rhodopsins which have one or two carboxylic acids near the retinal. Despite
these similar properties between bestrhodopsin and NeoR, the detailed photochemical properties of NeoR remained unknown.
Thus, we clarified the photochemical properties of NeoR using HPLC and spectroscopy.

Results

We studied a novel near-infrared light-absorbing
enzymerhodopsin from Obelidium mucronatum (OmNeoR).
OmNeoR show guanylyl cyclase activity upon light irradiation,
when it form heterodimers. Using UV-vis spectroscopy, it isrevealed that OmNeoR absorbs near infrared light, and its
absorption wavelength converts the dark state into a stable UVabsorbing state.
Using HPLC analysis which can determine composition ratioof retinal isomers in rhodopsin, anti-oxime peak (X) is observed
different from f 13-cis, 11-cis, 9-cis, or all-trans form. In
previous research, peak (X) is probably 7-cis. However, 7-cis
FIG.2 Retinal isomerization in NeoR andretinal is unstable, because of a steric hindrance between the 9photoreaction at low temperature.
methyl group and methyls in the β-ionone ring. In addition, an
HPLC peak of di-cis retinal oxime, such as the 9,11-di-cis form, can appear between those of 9-cis and all-trans retinal oxime.
Thus we weren't sure if peak (X) was really 7-cis form. Here, we isolate same isomer as peak (X) and measure the 1H NMR
spectra which is consistent with 7-cis form. Therefore, we conclude that peak (X) is 7-cis retinal.
In addition, OmNeoR show no photoreaction at <270K. It indicate that there exist potential barrier for 7-cis isomerizationin excited state of OmNeoR.
In this presentation, we would like to discuss the unique photoisomerization reaction of NeoR.

Reference

O.P. Ernst et al., Chem Rev, 114, 126-163 (2014).
A. Rozenberg et al. Nat. Struct. Mol. Biol, 29, 592−603 (2022)
3
M. Broser et al. Nat.Commun. 11, 5682 (2020)
1
2

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SE-03B-α2-10Development of a real-time 4D quantum temperature imaging system
to measure intercellular thermal diffusivity
Haruka Maeoka1, Ryuji Igarashi2, Shin Usuki3, and Takuma Sugi1
1

Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University
2
3

Quantum Science and Technology Organization

Research Institute of Electronics, Shizuoka University
m211518@hiroshima-u.ac.jp

Cellular function is severely affected by temperature change. Heat produced within a cell controls its own cellularfunction cell-autonomously and neighboring cells’ function non-cell-autonomously. While several studies havefocused on intracellular thermal diffusion, few have reported on how intercellular thermal diffusion influencesneighboring cells’ function. This question could be addressed by estimation of the intercellular thermal diffusivity,
which requires quantifications of temperatures at three-dimensionally distributed multiple cells during thermal
diffusion. However, assuming that the thermal diffusivity in cells is the same as that in water, 1.5×10-7 m2 / sec, ittakes 1 millisecond for heat to diffuse through multiple 10 μm cells in all XYZ directions. In contrast, when we takeimages using a 100 fps camera with 100 scans along Z-axis and 30 times data accumulations, current 3D imaging
technologies such as confocal microscopy take 50 milliseconds to measure temperature of multiple cells along Zaxis. This means that the measurement speed of the current technologies is insufficient to observe 3D intercellularheat diffusion which completes within 1 millisecond.
Recently, we developed the high-resolution light field microscopy (HR-LFM) capable of ‘scan-less’ 3D imaging
by capturing 3D space as a 2D image using a micro-lens array. We also focused on the fluorescent nanodiamonds(FNDs) which allow for highly sensitive temperature measurement. Here, these two cutting-edge technologies
inspired us to establish a system for measuring the temperatures of multiple cells with an acquisition rate faster thanheat diffusion rate. First, (1) we constructed a ‘selective imaging’ system to selectively extract the fluorescence of
only FNDs from among background fluorescence by irradiating microwave that induces electron spin resonance tomodulate the fluorescence of FNDs. Then, we synchronized ‘scan-less’ 3D detection of multiple signals by HRLFM with microwave irradiation. This enabled simultaneous selective extraction of multiple FNDs’ fluorescencefrom among fluorescent beads in a 3D sample and from among an autofluorescence in C. elegans, thereby achieving

3D selective imaging 50-fold faster than confocal microscopy. Second, (2) we attempted to establish the system formeasuring 3D heat diffusion. We successfully measured temperature changes at multiple 3D locations

simultaneously in nematode C. elegans, thus achieving 3D temperature imaging 100-fold faster than confocal

microscopy. Using this method, we will calculate the intercellular thermal diffusivity by measuring the intercellularheat diffusion from a heat source cell to neighboring cells in vivo.

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SE-03B-α2-11

Bidirectional neural network and its application toimage denoising, super-resolution, and image completion
Kei Majima1,2, Noriaki Yahata1

1

Institute for Quantum Life Science, National Institutes for Quantum Science and Technology (QST), Chiba, Japan
2

PRESTO, Japan Science and Technology Agency (JST), Japanmajima.kei@qst.go.jp

Introduction

Quantum sensing technology has enabled the development of new methods to visualize various physical parameters ofinterest in biological systems. For example, the concentration of specific molecules can be visualized by magnetic
resonance imaging (MRI), and an electromagnetic field or distribution of temperature can be reconstructed by nitrogenvacancy center sensing (NV-center sensing). Because observed image data are sometimes noisy/lowresolution/incomplete, image processing to recover clean/high-resolution/complete images from the observed ones is a
critical step that must be developed. In this report, we present a unified framework for the above-mentioned imageprocessing tasks using neural networks.

Methods

We describe our proposed framework by taking the super-resolution task as an example. Note that the same framework canalso be used for image denoising and image completion. In our framework, we assume that a set of low-resolution images
and the corresponding high-resolution images are available as training data. Then a bidirectional neural network, which is aneural network whose each layer is bidirectional, is trained using the training data (Fig 1A). Following the neural network
training, for new low-resolution images, the corresponding high-resolution images can be estimated using this neuralnetwork as a converter.

Results

Using two types of toy image data, we tested the proposed framework on three types of image-processing task: 1) image
denoising, 2) super-resolution, and 3) image completion. Results of the super-resolution task are shown in Fig. 1B and C.

FIG 1. Neural network-based image-preprocessing framework. A schematic of neural network
training (panel A) and results of the super-resolution task (panels B,C) are shown.

Discussion and Conclusions

In this report, we presented an image-processing framework using a bidirectional neural network, and our preliminary
results showed that this framework can effectively perform several types of image-processing task. The application to realexperimental data in the field of quantum sensing will be addressed in our future studies.

Acknowledgments

This research was supported by MEXT Q-LEAP (JPMXS0120330644), JSPS KAKENHI (20K16465), JST ERATO(JPMJER1801), and JST PRESTO (JPMJPR2128).

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SE-03B-α2-12

Molecular insight into photoactivation mechanism of BLUF protein
by QM/MM free energy simulation
Masahiko Taguchi, Shun Sakuraba, Justin Chan, and Hidetoshi Kono
Institute for Quantum Life Science, National Institutes for Quantum Science and Technology
taguchi.masahiko@qst.go.jp
Introduction
OaPAC is a photoactivated enzyme that forms a homodimer [1,2]. It has two BLUF photoreceptor domains
connected to the catalytic domains via long coiled-coil C-terminal helixes. It is thought that during
photoactivation, reorganization of hydrogen bonding network between Tyr6, Gln48, and chromophore andketo-enol tautomerization of Gln48 occur in the BLUF domain [3,4]. However, the free-energy profile of thephoto-isomerization reaction and how the structural change in the BLUF domain propagates toward thecatalytic domain have not been revealed yet.
MethodWe first focused on the BLUF domain dimer with the C-terminal helixes from the dark state X-ray
crystallographic structure of OaPAC [1]. We free-energetically optimized the dark state structure using
QM/MM RWFE-SCF method [5]. We considered two possible light state structures that were free-energetically
optimized. The free-energy differences between the dark and two light state structures were evaluated by thefree-energy perturbation calculation. To clarify differences in protein dynamics upon photo-isomerization, we
performed long-time MD simulations for the dark and light state structures.
Results
The free-energy difference between the two light state structures was estimated ~4.7 kcal/mol. The light statemodel with a lower free energy is consistent with a FTIR experiment result [4], but is inconsistent with lightstate X-ray crystallographic structure [2] in the assignment of nitrogen and oxygen atoms of Gln48 sidechain.
Our component analysis of free-energy difference between the dark and light state structures showed that thechemically unstable enol tautomer of Gln48 in the light state is stabilized by a strong hydrogen bonding
network with chromophore and Tyr6. Moreover, in the light state, we observed a flip of Trp90 nearby the Cterminal helix, causing the subsequent structural changes in the BLUF core and the C-terminal helix.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644.
References[1] M. Ohki et al., Proc. Natl. Acad. Sci. USA 113, 6659 (2016).
[2] M. Ohki et al., Proc. Natl. Acad. Sci. USA 114, 8562 (2017).
[3] T. Domratcheva et al., Sci. Rep. 6, 22669 (2016).
[4] T. Iwata et al., J. Am. Chem. Soc. 140, 11982 (2018).
[5] S. Hayashi et al., Annu. Rev. Phys. Chem. 68, 135 (2017).

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