The International Symposium on Quantum Science,
Technology and Innovation

Proceedings
Date �-� December ����Virtual Conference

Final Version

Table of contents
Program
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��

��-��

Welcome to Quantum Innovation ����Organizing Committee
Symposium Outline

Program��-��Program at a Glance

��-��Quantum Computing Track

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��
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Plenary Sessions

Quantum Cryptography &Communication Track
Quantum Sensing Track
Quantum Sensing Track��-��

Short Presentations by Young Researchers

��-��

Plenary Sessions

��-��Quantum Cryptography &Communication Track

Abstract

��-����-���

Quantum Computing Track
Quantum Sensing Track
Quantum Sensing Track���-���

Short Presentations by Young Researchers SE-��A

���-���

Short Presentations by Young Researchers SE-��B

Quantum Sensing Track

001

The International Symposium on Quantum Science,
Technology and Innovation
Welcome to Quantum Innovation ����It is our pleasure to invite all of you, scientists, engineers, academicians, young researchers,

business delegates and students, from all over the world to attend Quantum Innovation ����,the International Symposium on Quantum Science, Technology and Innovation, to be heldon �-� December ���� as Virtual Conference organized and served commemorating the birthof the Quantum Technology Innovation Hubs.

The aim of Quantum Innovation ���� is to bring together, a multi-disciplinary group of scientists

and engineers to present and exchange breaking-through ideas related to quantum technologies.
The topics of the meeting cover broad aspects of quantum technology including

quantum computing, quantum sensing, quantum cryptography and quantum communication
with a focus on the latest outstanding achievements in the field of quantum technology
and its future trends and needs.

We welcome you to Quantum Innovation ���� and look forward to your participation in the meetingwith distinguished speakers from different countries around the world sharing new and exciting
results and promoting collaborations in Quantum Technology.

002

Organizing Committee
ChairsGeneral Chair

Yasunobu Nakamura

RIKEN

Track Chair
Quantum Computing

Track Chair
Quantum Sensing

Track Chair
Quantum Cryptography & Communication

Osaka University

National Institutes for
Quantum Science and Technology（QST）

National Institute of Information
and Communications Technology（NICT）

Masahiro Kitagawa

Akinari Yokoya

Masahide Sasaki

Committee members
Keisuke Fujii

Takayuki Iwasaki

Kae Nemoto

Seiichiro Tani

Mikio Fujiwara

Takashi Kuroda

Tadashi Sakai

Yoshimichi Tanizawa

Takuya Hirano

Takahiro Mori

Masahiro Takeoka

Akihisa Tomita

Atsushi Mukaiyama

Shu Tanaka

Rodney Van Meter

Osaka University

NICT

Gakushuin University

Hiroshi Imai

The University of Tokyo

Tokyo Institute of Technology

National Institutefor Materials Science（NIMS）

National Instituteof Advanced Industrial Scienceand Technology（AIST）
Osaka University

National Instituteof Informatics (NII)

Tokyo Institute of Technology

Keio University

Keio University

Nippon Telegraphand Telephone Corporation（NTT）

Toshiba

Hokkaido University

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 ���� 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

�-� December ����Venue

Symposium is held on-line.
Schedule� December ����Plenary Sessions held in Tokyo

�-� December ����Quantum Computing Track
Quantum Sensing Track

Quantum Cryptography & Communication Track

Speakers

All the speakers are to be invited.
Language

EnglishParticipants
Researchers, engineers, business delegates, policy makers, administrators, students andmedia. All participants are required to register in advance. Registration page is open!

005

Symposium Sponsors
Cabinet Oﬃce

Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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)
Osaka University

Tokyo Institute of Technology

Symposium Supporters
Ministry of Internal Aﬀairs and Communications
Ministry of Economy, Trade and Industry

National Institute for Materials Science (NIMS)The University of Tokyo

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 ����.

・Quantum computer development hub in RIKEN

・Quantum device development hub 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 hub 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
RIKEN serves as Headquarters of the Hubs to incorporate eﬀorts to advancequantum technology research in Japan.

006

Program at a GlanceTracksPL

TracksPlenary Sessions

Quantum Computing Track

Contents / Topics

Contents / Topics

Ministries, Plenary Talks, Keynote SpeechesSuperconducting Quantum Computers(QC),

Welcome from Organizing Committee and HostingCP

Quantum Computing with Atoms and Ions,
Photonic QC,Young Researcher

Session, Quantum Simulations, Semiconductor QC,

Quantum Annealing Toward FTQC(Tutorial), Beyond
NISQ/Toward

FTQC Panel Discussion,Quantum Architechture,

Quantum Algorithms, NISQ Algorithms,Quantum
Algorithms for ChemistryCC
TracksQuantum Cryptography &Communication Track
Contents / Topics

SE
TracksQuantum Sensing Track
Contents / Topics

Quantum Internet, Quantum Cryptography(Up-to-date

Solid-State Quantum Sensors, Quantum Sensors for

Quantum Technology

Sciences, AtomTechnologies of Field and Satellite QKDs), Challenges for
Platform (QKD Networks, Satellite QKD and theirintegration), Industry Panel, Young Researcher Session**CC-�� on �th and CC-��, CC-�� on �th Dec aresupported by SIP (cross-ministerial Strategic Innovation
promotion Program).

Life Sciences, Quantum Sensors and Quantum LifeInterferometer, Cold Atom, Atomic/Ion Clocks, Short
Presentations by Young Researchers*�th Dec Sessions are a joint-program with The �th
IFQMS (The �th International Forum on Quantum
Metrology and Sensing).

007

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

Dec(Tue.)�������:��-��:��

Opening��:��-��:��PL-��

Plenary Talks

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Keynote SpeechesPL-����:��-��:��

Keynote Speeches(cont.)PL-����* �th IFQMS（International Forum on Quantum Metrology and Sensing)** SIP(cross-ministerial Strategic Innovation promotion Program)�

Dec(Wed.)������

�:��-�:��

Quantum Computing
with Atoms and Ions

�:��-��:��

CP-��

�:��-��:��

Quantum Internet ���:��-��:��

Superconducting
Quantum Computers

Solid-State Quantum Sensors � SE-��*

CP-��

CC-��

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Quantum Sensors
for Life Sciences

SE-��*

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Photonic Quantum
Computers

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Young Researcher Session

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Quantum Simulations

CP-��

CP-��

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Short Presentations
by Young Researchers
on SE-��,��,��,��
TopicsShort Presentations
by Young Researchers
on SE-��,��
TopicsSE-��A*

SE-��B*CP-��

��:��-��:��

Semiconductor
Quantum Computers��:��-��:��

CP-��

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Solid-State Quantum Sensors ���:��-��:��

Young Researcher SessionCC-����:��-��:��

SE-��*

Quantum Internet �CC-����:��-��:��

Quantum Sensors
and Quantum Life Sciences

SE-��*

��:��-��:��

Quantum Cryptography(Up-to-date Technologies ofField and Satellite QKDs)

CC-��**

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** SIP(cross-ministerial Strategic Innovation promotion Program)�

Dec(Thu.)������

�:��-�:��

Quantum Annealing �CP-��Toward FTQC

CP-��

Toward FTQC (Tutorial)

CP-���:��-�:���:��-��:��

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Beyond NISQ / Toward FTQC
Panel Discussion

�:��-��:��Atom Interferometers

SE-��

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Quantum Algorithms(Long-term)

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NISQ Algorithms

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Quantum Annealing ���:��-��:��

Quantum Algorithms
for Chemistry

��:��-��:��

Quantum Annealing �

CP-��

CP-��
CP-��
CP-��
CP-��

��:��-��:��Atom/Ion Clocks

SE-��

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Challenges for Quantum Technology
Platform(QKD Networks, Satellite QKD
and Their Integration)

��:��-��:��

Industry Panel Session

CC-��**009

Plenary Sessions

All the times in the program are Japan Standard Time(GMT+�)� Dec(Tue.)

��:��-��:��

Session / Presentation

Opening

Chairperson

Shigeo Koyasu

WelcomeTakayuki Kobayashi

WelcomeWelcome��:����:��-��:��

Chairperson / Presenter

Congratulatory Speech
BreakPL-��. Plenary Talks

Affiliation

Executive Diector, RIKEN

Yasunobu Nakamura

General Chair, QI���� Organizing Committee

Hideyuki Tanaka

State Minister of Education, Culture, Sports, Science and Technology

Keitaro Ohno

Minister of State for Science and Technology Policy

Parliamentary Association for Quantum Technology Promotion

Chairperson

Yasuhiko Arakawa

��:��National Quantum Initiative

Charles Tahan

��:��Quantum technology innovation for Society �.�

Makoto Gonokami

��:��Introduction of quantum business creation
consortium Q-STAR

Taro Shimada

��:��Quantum computer innovation in Japan

Kohei Itoh

President, Keio University

��:����:��-��:��BreakPL-��. Keynote Speeches

The University of Tokyo
Assistant Director for QIS and Director of the NQCO, OSTP,
White House, US

The University of Tokyo /Chair, Quantum Technology Committee,
Government of Japan

Corporate Senior Vice President and Chief Digital Officer,
Toshiba Corporation

PL-��-��PL-��-��PL-��-��PL-��-��Yasunobu Nakamura

General Chair, QI���� Organizing Committee

Novel directions for advancing satellite
based quantum communication

Thomas Jennewein

University of Waterloo

PL-��-����:��

Towards an experimental demonstrationof surface code quantum error correction

Hartmut Neven

GooglePL-��-��

��:��

Break
Hidetoshi Katori

The University of Tokyo

PL-��-��Quantum technology with spins

Jörg Wrachtrup

University of Stuttgart

PL-��-��

Towards a quantum internet: status,
challenges and progress

Ronald Hanson

QuTech, Delft University of Technology

PL-��-��

��:��

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��:��

Chairperson

Abstract PDF

Transportable optical lattice clocks to test
and use gravitational redshift

Closing010

Quantum Computing Track

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

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Session / Presentation

Chairperson / Presenter

Affiliation

Chairperson

Hiroki Takahashi

OIST

Quantum simulations and algorithms with ion trap systems

Christopher Monroe

Duke U / IonQ

CP-��. Quantum Computing with Atoms and Ions
Exploring frontiers of quantum science using programmable atom arrays
High performance commercial trapped ion quantum computers based on the QCCD architecture
BreakCP-��. Superconducting Quantum Computers
Chairperson

Mikhail Lukin

Patty Lee

Two-dimensional array of superconducting qubits with vertical accessYasunobu Nakamura

��:��-��:��

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��:��-��:��BreakCP-��. Photonic Quantum Computers

Akira Furusawa

UTokyo / RIKEN

BreakCP-��. Young Researcher Session

��:����:��-��:��

RIKEN

The hybrid quantum circuits with trapped electrons

Atsushi Noguchi

UTokyoCP-��. Quantum Simulations

Yutaka Tabuchi

RIKEN

Chairperson

Takeshi Fukuhara

RIKEN

Ultrafast and ultracold quantum simulator/computer with attosecond precision

Kenji Ohmori

IMS

Quantum simulation with ytterbium atoms in optical lattices
BreakCP-��. Semiconductor Quantum Computers

Shintaro Taie

Kyoto U

Chairperson

Takahiro Mori

AIST

Quantum computation - spins inside

Lieven Vandersypen

TU Delft

Engineering qubits in silicon with atomic precision

��:��Si platform for spin-based quantum computing

��:��PsiQuantum

Erika Kawakami

��:��
��:��

Pete Shadbolt

Chairperson

Break

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CP-��-��

Large-scale fault-tolerant universal quantum computing with quantum teleportation

��:��

��:��

RIKEN

RIKEN / UTokyo

Superconducting quantum- and digital-hybrid computers - tackling of increasing wirings

��:��-��:��

CP-��-��Atsushi Noguchi

Silicon photonic quantum computing

Closing

Michelle Simmons
Seigo Tarucha

CP-��-��

IBM

Chairperson

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CP-��-��

Google

��:��
��:��

Honeywell

Julian Kelly

Jerry Chow

Exponential suppression of bit or phase flip errors with cyclic error correction

CP-��-��

RIKEN

Challenges and directions of quantum computing with superconducting qubits

��:��Harvard U

Jaw-Shen Tsai

��:��

Abstract PDF

CP-��-��

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Silicon Quantum Computing

CP-��-��

RIKEN

CP-��-��

CP-��-��

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Quantum Computing Track� Dec(Thu.)

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Session / Presentation

CP-��. Quantum Annealing �
Chairperson

Next-generation quantum annealing testbed
BreakCP-��. Toward FTQC
Chairperson

Toward realization of quantum error correction andfault-tolerant quantum computing

Chairperson / Presenter

Affiliation

Shu Tanaka

Keio U

Yuuki Tokunaga

NTT

Keisuke Fujii

Osaka U / RIKEN / UTokyo

Keisuke Fujii

Osaka U / RIKEN / UTokyo

Robert Raussendorf

UBC

William Oliver

CP-��. Toward FTQC (Tutorial)
Chairperson

Fault-tolerance with bosonic qubits

Fault-tolerant quantum computation in with �D cluster states
Break

CP-��. Beyond NISQ / Toward FTQC Panel Discussion
Chairperson

Shruti Puri

CP-��-��

Masato Koashi

UTokyoCP-��-��Robert Raussendorf

UBC

Shruti Puri

Kosuke Fukui
Kae Nemoto

Yasunari Suzuki

Atsushi Noguchi

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CP-��-��Yale U

Keisuke Fujii

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CP-��-��BreakPanelists

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MIT

Abstract PDF

BreakCP-��. Quantum Algorithms (Long-term)
Chairperson

Provably accurate simulation of gauge theories and bosonic systems
Quantum algorithms for large-scale problems
BreakCP-��. NISQ Algorithms

Yutaka Tabuchi

Yale U
Osaka U
UTokyoNII

NTT

UTokyo /RIKEN
RIKEN

Hiroshi Imai

UTokyoFrançois Le Gall

Nagoya U

Yuan Su

GoogleChairperson

Seiichiro Tani

NTT

Development of quantum machine learning algorithms and experimental realization

Kosuke Mitarai

Osaka U

Promises and challenges of variational quantum algorithms
BreakCP-��. Quantum Annealing �
Chairperson

Patrick ColesLANL

Shu Tanaka

Keio U

Chairperson

Wataru Mizukami

Osaka U

Quantum computing for chemistry

Markus Reiher

ETH Zurich

Algorithmic breakeven in quantum annealing
Break

CP-��. Quantum Algorithms for Chemistry
Break down the high-order tensors of quantum chemistry, for O(N)-depth circuit algorithm
BreakCP-��. Quantum Annealing �
Chairperson

Improving adiabatic quantum computing with non-adiabatic methods
Closing

Daniel Lidar

Yuki Kurashige

Shu Tanaka

Wolfgang Lechner

CP-��-��

USC

Kyoto U

Keio U

U Innsbruck

CP-��-��
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CP-��-��

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012

Quantum Cryptography & Communication Track

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

Session / Presentation

Chairperson / Presenter

Affiliation

Chairperson

Kae Nemoto

NII

Quantum controlled routers and quantum data centers

Liang Jiang

U Chicago

�:�� - ��:��CC-��. Quantum Internet ��:�� - �:��Bringing QKD to real-world digital infrastructures�:�� - ��:��

��:�� - ��:��

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Ion-photon interface for quantum networks
Designing tomorrow’s quantum internet
BreakCC-��. Young Researcher Session

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(Thu.)

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NTT

Panelist

Shota Nagayama

Mercari

Panelist
BreakCC-��. Quantum Internet �

Mariko Kobayashi

Wojciech Kozlowski
Toshihiko Sasaki

Tomoyuki Horikiri

UTokyoYNU

NTTSoftware and protocol stacks for quantum networks

Wojciech Kozlowski

TU Delft

Angela Cacciapuoti

Genuine and optimized entanglement-based quantum networks

Wolfgang Duer

Entanglement based quantum networking

Siddarth Joshi

Quantum physical unclonable functions and their comprehensive cryptanalysis
Break

Elham Kashefi

CC-��-��

TU Delft

Koji Azuma

Quantum Internet: from classical to quantum paths

CC-��-��

Mercari

Chairperson

U Naples Federico II

CC-��-��

U InnsbruckCC-��-��

U Edinburgh / CNRS Sorbonne U
U BristolCC-��-���

CC-��-��CC-��-��CC-��. Quantum Cryptography (Up-to-date Technologies of Field and Satellite QKDs) [SIP(cross-ministerial Strategic Innovation promotion Program)]
Chairperson

Masahiro Takeoka

Keio U

OpenQKD use-case demonstrations in Europe

Andreas Poppe

AIT

Opening Remarks

Lessons from the SpooQy-� satellite

High-level concepts and design of commercial satellite-based QKD networks
Break

Hideyuki Tokuda
Alexander Ling
Manuel Erhard

NICT

CC-��-��

NUS

CC-��-��

qtlabsCC-��-��CC-��-��Quantum networking research at Los Alamos

Raymond Newell

LANL

CC-��-��

Finite-key security of continuous-variable quantum key distribution

Masato Koashi

UTokyoCC-��-��

Fundamentally applied quantum communication
Closing

Session / Presentation

Rob Thew

Chairperson / Presenter

U Geneva

Affiliation

CC-��-��

Abstract PDF

CC-��. Challenges for Quantum Technology Platform (QKD Networks, Satellite QKD and Their Integration)[SIP(cross-ministerial Strategic Innovation promotion Program)]
Chairperson

Kaoru Kenyoshi

NICT

Secure information society using "Quantum Secure Cloud"Mikio Fujiwara

NICT

Overview of Japanese project “SIP” and quantum secure could technologies

Masahide Sasaki

Quantum key distribution research and development in NEC

Junich Funada

Quantum communication activities in Canada

Norbert Lütkenhaus

QKD R&D and field trials in Toshiba
Break

Yoshimichi Tanizawa

CC-��. Industry Panel Session[SIP(cross-ministerial Strategic Innovation promotion Program)]
Chairperson

CC-��-��

NEC

CC-��-��

Toshiba

U Waterloo

NICT

David Williams

ArQiT

Andrew Lord

Hyung-Soo (Hans) Kim
Closing

NICT

Masahide Sasaki

Diego Lopez

��:��

OIST

Keio U

Panelist

��:�� - ��:��

William Munro

CC-��-��

Rodney Van Meter

Panelist

��:��-��:��

Hiroki Takahashi

U Waterloo

Chairperson
Facilitator

��:��Michele Mosca

Abstract PDF

Venkat Josyula

CC-��-��CC-��-��CC-��-��

BT

TelephonicaKT

Verizon013

Quantum Sensing Track

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

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Session / Presentation

Chairperson / Presenter

Affiliation

Chairperson

Takeshi Ohshima

QST

Current status and prospects of solid-state quantum sensors for Quantum-LEAP

Mutsuko Hatano

Tokyo Tech

Nanoscale vector AC magnetometry with a single nitrogen-vacancy centerin diamond
Planetary magnetic field sensing via electrical readout of quantum centers in SiC

SE-��. Solid-State Quantum Sensors � [�th IFQMS]
Quantum sensing of quantum materials using NV center microscopy

BreakSE-��. Quantum Sensors for Life Sciences [�th IFQMS]

Amir Yacoby

Abstract PDF

Harvard U

SE-��-��

Paola CappellaroMITSE-��-��Corey Cochrane

JPL Caltech

SE-��-��

SE-��-��

Chairperson

Hiroshi Yukawa/Kensuke Osada QST
Olga Shenderova

Adámas Nanotechnologies

SE-��-��

Nitrogen-vacancy centers in nanodiamonds as temperature sensors andimmunoassay reporters

Huan-Cheng Chang

Academia Sinica

SE-��-��

Shun Kishimoto

NIH

SE-��-��

Production of color centers in nanodiamond

Treatment responses to immune checkpoint inhibitor therapy evaluated by MRI
BreakSE-��A. Short Presentations by Young Researchers on SE-��, ��, ��, �� Topics [�th IFQMS]

SE-��A

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

SE-��B

Break-out Sessions
BreakSE-��. Solid-State Quantum Sensors � [�th IFQMS]
Chairperson

Takayuki Iwasaki

Tokyo Tech

Programmable quantum simulators based on spins in diamond

Tim Taminiau

TU Delft

Quantum sensing enabled by spin qubits in diamond

Development and optimisation of diamond for quantum technologies
BreakSE-��. Quantum Sensors and Quantum Life Sciences [�th IFQMS]

Fedor Jelezko

Matthew Markham

Ulm U

SE-��-��Element Six

SE-��-��

Chairperson

Ryuji Igarashi

QST

Avian magnetoreception ‒ a radical sense of directionPeter HoreU Oxford

Quantum biology: an Introduction

Surface chemistry of diamond for quantum applications

Diamond-based quantum sensors: technology and applications in physics and biology
Closing

Session / Presentation

Johnjoe McFadden
Anke Krüger

Christian Degen

U Surrey

SE-��-��

U Stuttgart

SE-��-��

ETH Zurich

Chairperson / Presenter

Affiliation

Chairperson

Takashi Mukaiyama

Osaka UClassical and quantum sensing for precise inertial navigation

Mikio Kozuma

Tokyo Tech

SE-��. Atom Interferometers
Tests of quantum mechanics and gravity with atom interferometry
Rotation sensing with the BIGTOP gyroscope

Development of transportable atomic gravimeters for field applications
BreakSE-��. Atom/Ion Clocks

Mark Kasevich
Cass Sackett

Ken'ichi Nakagawa

SE-��-��

UEC

Optical clocks based on multi-ion systems

Kazuhiro Hayasaka

NICT

Lattice clock as a frequency standard for JST and UTC
Closing

Christian Lisdat
Tetsuya Ido

Abstract PDF

U Virginia

RIKEN

Strontium lattice clocks at PTB: transportable and in the lab

SE-��-��

SE-��-��

Masao Takamoto
Murray Barrett

SE-��-��

Stanford U

Chairperson

A Lu+ optical clock

SE-��-��

SE-��-��
SE-��-��

NUS

SE-��-��

PTB

SE-��-��

NICT

SE-��-��
SE-��-��

014

Quantum Sensing Track : Short Presentations by Young Researchers

SE-��A. Short Presentations by Young Researchers on SE-��, ��, ��, �� Topics [�th 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+�)� Dec(Wed.)

Session / Presentation

Mentor / Presenter��:��-��:��

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

��:��-��:��

SE-��A-α�MentorFedor Jelezko

Ulm U

Mentor

Masaki Sekino

U TokyoMentorChair

Takeshi Ohshima
Takayuki Iwasaki

Motofumi Fushimi

QST

Tokyo TechU TokyoCo-chairChikara Shinei

Exploring NV center formation condition for high Econv andcharge-state ratio of NV- and NV� centers

Chikara Shinei

NIMS

SE-��A-α�-��

Sensitive atomic magnetometer beyond the standard quantum limit

Kosuke Shibata

Gakushuin U

SE-��A-α�-��Imaging hydrodynamic flow in WTe_� using cryogenic quantum
magnetometry

Uri Vool

Harvard U

SE-��A-α�-��

Toward on-board magnetoencephalography with wearable
magnetometers and active noise canceler

Xinyu CaoU TokyoSE-��A-α�-��

Continuous-wave temperature sensing using RF-dressed statesof nitrogen-vacancy centers in diamond

Hibiki Tabuchi

Keio U

SE-��A-α�-��

High-quality lead-vacancy centers in diamond by high-pressure andhigh-temperature annealing

Peng Wang

Tokyo Tech

SE-��A-α�-��

Magnetocardiography imaging of living rats using NV centers in Diamond

Ryoma Matsuki

Tokyo Tech

SE-��A-α�-��MentorSatoshi Yamasaki

Kanazawa U

MentorToshiharu Makino

AIST

SE-��A-β�
MentorTokuyuki Teraji

MentorAkimichi Nakazono

Co-chairMoriyoshi Haruyama

Chair

Hiroki Morishita

NIMS

NIMS

YAZAKI

Kyoto UAIST

Probing correlated phenomena in �D materials withdiamond quantum sensors

Mark Ku

U Delaware

SE-��A-β�-��

Electroluminescence observation of NV center in diamondlateral p-i-n diodeMoriyoshi Haruyama

AISTSE-��A-β�-��

Synthesis of HPHT diamond with controlled nitrogen concentration

Masashi Miyakawa

NIMS

SE-��A-β�-��

Takeyuki Tsuji

Tokyo Tech

SE-��A-β�-��Tokyo Tech

Vector DC magnetic field sensing with the reference microwave fieldusing nitrogen vacancy centers in diamond

Yuta Shigenobu

SE-��A-β�-��

Takuya Isogawa

Keio U

SE-��A-β�-��

Thermal effects on generation of spin defects in hexagonal boron nitride

Tetta Suzuki

Saitama U / QST

SE-��A-β�-��Mentor

Keiichi Edamatsu

Tohoku U

MentorHirotaka Terai

NICT

Formation of diamond film containing perfectly aligned NV center
ensembles at a high growth rate by high-power density plasma CVD

High dynamic range current detection using a diamond quantum sensor

��:��-��:��

Abstract PDF

Break-out Sessions

Mentor��:��-��:��

Affiliation

SE-��A-γ�
MentorRyosuke Shimizu

MentorRyo Okamoto

Co-chair

Le Bin Ho

Chair

Fumihiro China

Error-disturbance uncertainty relations in faraday measurements

Le Bin Ho

Wavelength-tunable broadband infrared quantum absorption
spectroscopy in the mid-infrared region �-� µm

Hydrogen annealing effect on silicon optical waveguide

Evaluation of superconducting nanowire single photon detectors
for mid-infrared wavelengths

UEC

Kyoto U
NICT

Tohoku U

Tohoku U

SE-��A-γ�-��

Masaya Arahata

Kyoto U

SE-��A-γ�-��Yuki Gama

Kyoto U

SE-��A-γ�-��

Yixin Wang

Tohoku U

SE-��A-γ�-��

015

Dec

(Wed.)

Session / Presentation

Mentor / Presenter

Affiliation

Phase retrieval of joint spectral amplitude

Kemeng Chen

UEC

SE-��A-γ�-��Hiroki Oshima

UEC

SE-��A-γ�-��MentorTakuya Hirano

Gakushuin U

Mentor

Masaki AndoU TokyoTemporal shaping of an entangled-photon wave packet
by fourier optical synthesis

��:��-��:��

SE-��A-δ�
MentorMentorTadashi Sakai

Co-chairSatoru Takano

Chair

Satoru Takano

Suspension noise measurements of cryogenic torsion pendulums
with crystaline fibrfibres
Towards sensitive accelerometers with levitated single nanoparticles

Kiyotaka Aikawa

Osaka UTokyo Tech
Tokyo TechU Tokyo

U TokyoSE-��A-δ�-��

Ching Pin Ooi

U TokyoSE-��A-δ�-��

Angular sensor with a coupled cavity for gravity gradient sensing

Yuka Oshima

U TokyoSE-��A-δ�-��

Interferometric gyroscope using slow and continuous atomic beam

Tomoya Sato

Tokyo Tech

SE-��A-δ�-��

Tokyo Tech

SE-��A-δ�-��

Ryoichi Saito

Osaka U

SE-��A-δ�-��

Karol Gietka

OIST

SE-��A-δ�-��

MentorFedor Jelezko

Ulm U

Mentor

Masaki Sekino

U TokyoExponentially enhanced quantum metrology by quenchingsuperradiant light-matter systems beyond the critical point
SE-��A-α�MentorTakeshi Ohshima

MentorTakayuki Iwasaki

Co-chairMotofumi Fushimi

Chair

Chikara Shinei

QST

Tokyo TechNIMSU TokyoThree-layered magnetically shielded room for ultrahigh-sensitivity
quantum sensing of biomagnetic signals

Motofumi Fushimi

U TokyoSE-��A-α�-��Super-resolution in nanoscale NMR

Nicolas Staudenmaier

Ulm U

SE-��A-α�-��Ryota Kitagawa

Tokyo Tech

SE-��A-α�-��Study on electron spin control method for high-sensitivity
diamond quantum sensor

Hiroyoshi Tomioka

Tokyo Tech

SE-��A-α�-��

Optically detected magnetic resonance spectra of silicon vacancies
in �H-SiC with different temperatures

Shu Motoki

QST / Saitama U

SE-��A-α�-��High efficiency formation of NV center inside diamondby femtosecond laser

Ryusei Yanoshita

Kyoto U

SE-��A-α�-��MentorSatoshi Yamasaki

Kanazawa U

MentorToshiharu Makino

AIST

Sensitivity of weight imaging using a hybrid system based on
piezoactive magnetic material and diamond quantum sensor

��:��-��:��

Kiyotaka Aikawa

Cryogenic monolithic interferometer for sensing gravity gradientDevelopment of a quantum gyroscope based on a signle ion trapping
techniques

��:��-��:��

Takashi Mukaiyama

Abstract PDF

SE-��A-β�
MentorTokuyuki Teraji

MentorAkimichi Nakazono

Co-chair

Hiroki Morishita

Chair

Moriyoshi Haruyama

NIMS

YAZAKIAIST

Kyoto UAC magnetic field sensing with ensemble NV centers using
electrical detection methods

Hiroki Morishita

Kyoto U

SE-��A-β�-��

OPuS-MAGNM - miniaturized optically pumped solid state quantum
magnetometers for space applications

Hannes Kraus

NASA

SE-��A-β�-��

Development of phthalocyanine ion beam for creation of multiple
NV centers.

Kosuke Kimura

QST, Gunma U

SE-��A-β�-��

016

Dec

(Wed.)

��:��-��:��

Session / Presentation

Mentor / Presenter

Affiliation

Abstract ID

Fabrication of diamond protective film using microwave plasma CVD
towards high-quality quantum emitters

Kazuki Hirokawa

Tokyo Tech

SE-��A-β�-��A compact quantum sensor head with side excitation of CVD diamond

Yuki Nishio

Tokyo Tech

SE-��A-β�-��Hybrid integration of Si�N� grating structure on diamond NV substrate
for efficient photon extraction

Ryota Katsumi

Toyohashi Tech

SE-��A-β�-��Mentor

Keiichi Edamatsu

Tohoku U

MentorRyosuke Shimizu

UEC

SE-��A-γ�
MentorKenichi Nakagawa

MentorHirotaka Terai

Co-chair

Fumihiro China

Chair

Le Bin Ho

UEC

NICT

Tohoku U
NICTSuperconducting nanostrip single-photon detectors
with dielectric multilayer cavities

Fumihiro China

NICT

SE-��A-γ�-��

Estimation of the quantum efficiency of the up-conversion system
based on injection-locked dual oscillators

Masayuki Hojo

Kyoto U

SE-��A-γ�-��

Selective measurement of biexciton luminescence by photon
correlation spectroscopy

Hiroya Seki

UEC

SE-��A-γ�-��

Towards optical manipulation of gold-nanoparticles for efficient
single photon sources

Rui SunTohoku U

SE-��A-γ�-��

Single photon emission from a quantum-dot-gold-nanostar coupledsYining Xuan

Yining Xuan

Tohoku U

SE-��A-γ�-��

Focusing constraints on coupling efficiency of collinear type-I
degenerated SPDC photon pairs into a single-mode fiber

Nicolas Schwaller

Kyoto U

SE-��A-γ�-��

017

Quantum Sensing Track : Short Presentations by Young Researchers

SE-��B. Short Presentations by Young Researchers on SE-��, �� Topics [�th 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+�)� Dec(Wed.)

��:��-��:��

Session / Presentation

Affiliation

Abstract ID

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

U Surrey

MentorMaeda Kiminori

Saitama U

MentorChair

Co-chair��:��-��:��

Mentor / Presenter

Tanaka Shigenori
Yahata Noriaki

Yokoya Akinari

Kobe UQST
QSTIntracellular thermal conductivity determined by dual-functionalized
diamond nanosensor

Suzuki Madoka

Osaka U

SE-��B-��-��

Label-free analysis of diffusion constant in lipid bilayers using nanoscalediamond magnetometry

Ishiwata Hitoshi

QST

SE-��B-��-��Temperature sensing using silicon vacancy centers in detonation
nanodiamonds

Fujiwara Masanori

Kyoto U

SE-��B-��-��

Quantum-inspired machine learning for exponentially big neuraldata analysis

Majima Kei

QSTSE-��B-��-��

Empirical verification of the violation of the temporal Bell inequality
in bistable perception

Aizawa Yasunori

QST

SE-��B-��-��

Tracking radiation damage induction pathway following core-holecreation of DNA molecules in aqueous solution in aqueous solution

Kumagai Yoshiaki

TUAT

SE-��B-��-��

MentorPeter HoreU Oxford

MentorShigeta Yasuteru

U Tsukuba

SE-��B-��
MentorIshizaki Akihito

IMS

Chair

Takakusagi Yoichi

High-resolution structure of an electron-transfer protein
by neutron crystallography

Hanazono Yuya

TMDU

SE-��B-��-��

Fabrication of a quantum sensor to reveal a topic in thermal physiology

Ishii Shuya

QST

SE-��B-��-��

So KitKyoto U

SE-��B-��-��

Formation of flavin anion and tyrosine radicals in avian Cryptochrome�Otsuka Hiroaki

Waseda U

SE-��B-��-��

Do neural activities of binocular rivalry follow a quantum probability
model? A test of temporal Bell inequalities

Hirao Takahiro

QST

SE-��B-��-��

X-ray absorption spectroscopy of a silicon phthalocyanine derivative,IR���, for X-ray excited photoimmunotherapy

Izumi Yudai

QST

SE-��B-��-��

Magnetically sensitive radical pairs in avian cryptochrome � proteins

Xu Jingjing

U Oldenburg

SE-��B-��-��

Co-chairInvestigation of irradiation induced nitrogen-vacancy centersin �-nanometer-sized detonation nanodiamonds

Imaoka Tatsuhiko

QST
QST

018

Abstract

TracksPL

TracksPlenary Sessions

Quantum Computing Track

Contents / Topics

Contents / Topics

Ministries, Plenary Talks, Keynote SpeechesSuperconducting Quantum Computers(QC),

Welcome from Organizing Committee and HostingCP

Quantum Computing with Atoms and Ions,
Photonic QC,Young Researcher

Session, Quantum Simulations, Semiconductor QC,

Quantum Annealing Toward FTQC(Tutorial), Beyond
NISQ/Toward

FTQC Panel Discussion,Quantum Architechture,

Quantum Algorithms, NISQ Algorithms,Quantum
Algorithms for ChemistryCC
TracksQuantum Cryptography &Communication Track
Contents / Topics

SE
TracksQuantum Sensing Track
Contents / Topics

Quantum Internet, Quantum Cryptography(Up-to-date

Solid-State Quantum Sensors, Quantum Sensors for

Quantum Technology

Sciences, AtomTechnologies of Field and Satellite QKDs), Challenges for
Platform (QKD Networks, Satellite QKD and theirintegration), Industry Panel, Young Researcher Session**CC-�� on �th and CC-��, CC-�� on �th Dec aresupported by SIP (cross-ministerial Strategic Innovation
promotion Program).

Life Sciences, Quantum Sensors and Quantum LifeInterferometer, Cold Atom, Atomic/Ion Clocks, Short
Presentations by Young Researchers*�th Dec Sessions are a joint-program with The �th
IFQMS (The �th International Forum on Quantum
Metrology and Sensing).

019

PL-01-03

Quantum technology innovation for Society 5.0
Makoto Gonokami
Graduate School of Science, the University of Tokyo, Japan

Abstract
We are facing major global challenges such as global warming andpandemic. Both are caused by human behavior, and cross-bordercooperation is essential. Appropriate use of data in cyberspace toencourage behavioral change is the key to solutions.

With recent DX, the integration of the real world and cyberspace isaccelerating. Digital technologies connect people in remote places, andreduce disparities across age, ability, gender, race, or location. In Japan, allsectors including the government, industry and academia are working

together to realize this ideal future, which we call Society �.�. In order torealize Society �.�, it is crucial to secure trust in the cyberspace.

Nature is driven by physical, chemical, and biological mechanisms, but

humanity has not yet fully unveiled and utilized them. Emerging quantum
technology is one of them, and the unused principles of quantum

mechanics are about to be utilized. We should continue basic research toexpand our wisdom. Fostering next generation is further important. Under
this situation, I believe the role of the academia that have diverse

knowledge is becoming more and more important. The daily collaboration
among top scientists transcending countries is indispensable.

020

PL-01-04

Introduction of quantum business creation
consortium Q-STAR
Taro Shimada
Toshiba SVP Chief Digital Officer

Abstract���� was year of Quantum Business Consortium around world. In Europe

and Asia many countries and relation started Business creation Consortium.

In Japan �/�/���� Q-STAR was formed. This consortium started with already�� member leading companies and ventures, but expands in rapidly. At thissession mission and scope and ambition of Q-STAR will be explained. Also

how it’ s ﬁt to existing organization and accelerate entire Quantum activity
in Japan towards Quantum Transformation namely QX.

021

PL-01-05

Quantum computer innovation in Japan
Kohei Itoh
Keio University

Abstract
Quantum technology is expected to advance the basis of entire current
information technology. This talk overview a variety of research anddevelopment in Japan towards realization of useful quantum computers.

022

PL-02-01

Novel directions for advancing satellite
based quantum communication
Thomas Jennewein
Institute for Quantum Computing, University of Waterloo, Canada

Abstract
Extending today’ s internet, the Quantum Internet will readily transfer

quantum bits, rather than classical bits, between users near and far andover multiple diﬀerent channels and could be used for securecommunications, quantum computer networks and metrologicalapplications. I will discuss recent advances on implementations and tools
useful for generating and distributing photonic quantum entanglement

over large distances using satellites. I will present some recent research on
quantum channel advancements including time-bin encoding,reference-frame-free protocols and single-photon emitters. I will alsopresent an overview of the upcoming Canadian quantum communication
satellite QEYSSAT.

023

PL-02-02

Towards an experimental demonstrationof surface code quantum error correction
Hartmut Neven
GoogleAbstract
The Quantum AI team is working on experimentally demonstrating that

surface code error correction reduces the logical error rate as one moves

from smaller to larger grids of data qubits. To achieve this multiple sourcesof error have to be reduced simultaneously. Besides �- and �-qubit gateerrors and readout errors, idling errors, crosstalk and leakage need to beaddressed. While making progress on our roadmap towards an error

corrected quantum computer we are also designing quantum algorithms forour current processors with the goal to compute scientiﬁcally orcommercially interesting quantities beyond the reach of classicalcomputers. This presentation will describe circuits to i) computeout-of-time-order correlators, ii) study the properties of a realization of time
crystals and iii) implement a quantum machine learning algorithm that

achieves exponentially reduced sample complexity as compared to classicalmachine learning techniques.

024PL-02-03

Transportable optical lattice clocks to test
and use gravitational redshift
Hidetoshi Katori
Department of Applied Physics, Graduate School of Engineering, The University of Tokyo,
Bunkyo-ku, Tokyo 113-8656, Japan.

Abstract
Clocks are devices to share time using ubiquitous oscillatory phenomena innature. We once relied on astronomical observations, and today we use far
regular oscillations of cesium atoms to deﬁne the international system ofunit (SI) for time, i.e., the SI second. Recent optical atomic clocks havedemonstrated more than ���-fold improvement over cesium clocks, leading
to a redeﬁnition of the second in the future. This extreme precision, in turn,allows clocks to investigate relativistic spacetime curved by gravity, whereclocks serve as gravitational potential sensors. Roles of the clocks are
rapidly changing from those supposed previously.

An “optical lattice clock” proposed in ���� beneﬁts from a low

quantum-projection noise by simultaneously interrogating a large numberof atoms trapped in optical lattices. About a thousand atoms enable suchclocks to achieve ��-�� instability in a few hours of operation. This superb
stability is especially suitable for relativistic geodesy, where gravitational
redshift between the clocks resolves a centimeter height diﬀerences.

We overview the progress of optical lattice clocks and address recent topics
including �) transportable optical clocks operated at a broadcasting tower,
TOKYO SKYTREE, to test gravitational redshift and �) an on-vehicle opticalclock and its applications.

025

PL-02-04

Quantum technology with spins
Jörg Wrachtrup
3rd Institute of Physics, Centre for Applied Quantum Technologies
and IQST, University of Stuttgart, Germany

Abstract
Spins in wide band gap semiconductors are a leading contender in various

areas of quantum technology. Most notably they have been established as anovel tool for nanoscale sensing, major hardware for long distancequantum entanglement, as well as small scale quantum registers forquantum computing. I will present the use of spins in in those areas [�,�,�].
Speciﬁcally, I will discuss quantum sensing with spins to investigate

magnetism in �D materials including the investigation domain patterns [�]and Moiré structures in twisted �D layers. Here the nitrogen vacancy centerin diamond is used to probe and image electronic magnetism in mono- andmultilayers of materials like CrBr�. By using dedicated measurements

strategies based on quantum algorithms one can enhance the performanceof those quantum sensors to achieve better signal quality and improve thespectral resolution in those measurements. [�].

[�] T. Oeckinghaus et al., Nano Lett. ��, ��� (����)[�] N. Morioka et al. Nature Com. ���� (����)[�] N. Chejanovsky et al. Nature Mat. ��, ���� (����)[�] Qi-Chao Sun et al. Nature Com. ��, ���� (����)[�] V. Vorobyov et al., arxiv����.�����.(����)026

PL-02-05

Towards a quantum internet: status,
challenges and progress
Ronald Hanson
QuTech, Delft University of Technology, The Netherlands

Abstract
Future quantum networks [�] may harness the unique features ofentanglement in a range of exciting applications such as blind quantum

computation in the cloud, secure communication and enhanced metrology.
To fulﬁll these promises, a strong worldwide eﬀort is ongoing to gain

precise control over the full quantum dynamics of multi-particle nodes andto wire them up using quantum-photonic channels.

Here I will brieﬂy introduce the ﬁeld of entanglement-based quantum

networks and discuss some of the current status and challenges. I will thengive an overview of our latest work on the realization of a multi-node

network in the lab including ﬁrst protocols and teleportation [�,�], on
increasing the distance between nodes to metropolitan scales, ondevelopment of next-generation devices with improved quantum

spin-photon interfaces, and on the development of a quantum network
control stack.

[�] Quantum internet: A vision for the road ahead, S.D.C. Wehner, D. Elkouss,
R. Hanson, Science ���, eaam���� (����).

[�] Realization of a multi-node quantum network of remote solid-state

qubits, M. Pompili, S.L.N. Hermans, S. Baier et al., Science ���, ��� (����)[�] Qubit teleportation between non-neighboring nodes in a quantum
network, S.L.N. Hermans, M. Pompili et al., arXiv:����.����� (����).

027

Abstract

PL
TracksPlenary Sessions
Contents / Topics

Welcome from Organizing Committee and Hosting
Ministries, Plenary Talks, Keynote Speeches

CP
TracksQuantum Computing Track
Contents / Topics

Quantum Computing with Atoms and Ions,

Superconducting Quantum Computers(QC),
Photonic QC,Young Researcher

Session, Quantum Simulations, Semiconductor QC,

Quantum Annealing Toward FTQC(Tutorial), Beyond
NISQ/Toward

FTQC Panel Discussion,Quantum Architechture,

Quantum Algorithms, NISQ Algorithms,Quantum
Algorithms for ChemistryCC
TracksQuantum Cryptography &Communication Track
Contents / Topics

SE
TracksQuantum Sensing Track
Contents / Topics

Quantum Internet, Quantum Cryptography(Up-to-date

Solid-State Quantum Sensors, Quantum Sensors for

Quantum Technology

Sciences, AtomTechnologies of Field and Satellite QKDs), Challenges for
Platform (QKD Networks, Satellite QKD and theirintegration), Industry Panel, Young Researcher Session**CC-�� on �th and CC-��, CC-�� on �th Dec aresupported by SIP (cross-ministerial Strategic Innovation
promotion Program).

Life Sciences, Quantum Sensors and Quantum LifeInterferometer, Cold Atom, Atomic/Ion Clocks, Short
Presentations by Young Researchers*�th Dec Sessions are a joint-program with The �th
IFQMS (The �th International Forum on Quantum
Metrology and Sensing).

028

CP-01-01

Exploring frontiers of quantum science using
programmable atom arrays
Mikhail Lukin
Department of Physics, Harvard University, United States

Abstract
We will discuss the recent advances involving programmable, coherent

manipulation of quantum many-body systems using neutral atom arrays
excited into Rydberg states, allowing the control over ��� qubits in

two-dimensional arrays. Recent results involving the realization of exotic
phases of matter, study of quantum phase transitions and exploration of
their non-equilibrium dynamics will be presented. In particular, we willreport realization and probing of quantum spin liquid states - the exotic

states of matter have thus far evaded direct experimental detection. Finally,
most recent progress involving testing quantum optimization algorithms

and realization of novel architecture based on dynamically reconﬁgurable

entanglement will be described. Prospects for scaling up these techniques,
including realization of large-scale quantum processors and quantum
simulators will be discussed.

029

CP-01-02

Quantum simulations and algorithms
with ion trap systems
Christopher Monroe
Duke University Depts of ECE and Physics and IonQ, Inc.

Abstract
Laser-cooled trapped atomic ions are well-established as possessing thehighest performance of any platform for quantum computing. But asimportantly, the path to scaling trapped ion quantum computers involves
well-deﬁned architectural plans, from shuttling ions between quantum

processor unit (QPU) cores and modular photonic interconnects between
multiple QPUs to gradual error-correction strategies. Full-stack ion trap

quantum computers have thus moved away from the physics of qubits andgates and toward the engineering of optical control signals, quantum gatecompilation for algorithms, and high level system design considerations.

I will summarize the state-of-the-art in these quantum computers, covering

recent algorithms and quantum simulations of physical processes, andspeculate on how they might be used in the future.

030

CP-01-03

High performance commercial trapped ion quantum
computers based on the QCCD architecture
Patty Lee
Honeywell Quantum Solutions

Abstract
Honeywell Quantum Solutions launched its ﬁrst commercial trapped-ion

quantum computer in ����, designed around the quantum charge-coupleddevice (QCCD) architecture. By applying fast transport operations to reorderand position ion qubits across multiple trapping zones simultaneously on
the device, the QCCD architecture creates a fully-connected, high ﬁdelity,

and scalable quantum computer. These systems oﬀer the unique capabilityof performing conditional quantum operations dependent on mid-circuit

measurement outcomes, and qubits can be re-used in the same circuit after
measurements. This feature allows users to perform eﬃcient quantum
simulations and execute repeated cycles of quantum error correction,

which was demonstrated for the ﬁrst time on System Model H�. Recently,
the system became the ﬁrst quantum computer to pass the quantum

volume ���� benchmark, the largest quantum volume ever measured on acommercial quantum computer. Future generation systems will incorporate
new technologies such as �D trap architectures and integrated photonics, inorder to scale the number of physical qubits and further increase system
performance.

031

CP-02-01

Challenges and directions of quantum computing
with superconducting qubits
Jerry Chow
IBM Quantum

Abstract
The ﬁeld of quantum computing has evolved into a large interdisciplinary
community that includes experts from all domains including industry,

government, and academia. As a result, we have seen accelerated progress
towards understanding the scope of quantum computing, pushing its

hardware and software technology, developing applications, and advancing
error mitigation/correction protocols. In this talk, I would like to present aview on how to progress technologies for quantum computing systems using
key metrics - scale, quality, speed that indicate the level of performance of aquantum computer. I will overview the recent development ofsuperconducting quantum computing systems and the scientiﬁc advancesby IBM that enabled to scale superconducting qubits to ��-qubit and��-qubit processors. As quantum computing is becoming a research tool, I
will discuss how we harness the computational power of a quantum

computer in machine learning and chemistry by integrating with classicalcomputing resources and using error mitigation. Exploiting classicalresources will allow us to extend the computational capacity that the current
limits of the quantum hardware can oﬀer.

032

CP-02-02

Exponential suppression of bit or phaseflip errors with cyclic error correction
Julian Kelly
Hardware Lead: System Control, Google Quantum AI

Abstract
Many promising practical applications using quantum computers will

require error rates below �e-��, but state-of-the-art hardware featuresphysical error rates near �e-�. Quantum error correction theoreticallypromises to bridge this divide by combining physical qubits into logicalqubits, and exponentially reducing error rates according to the number ofphysical qubits used. In this work, we run distance �-�� repetition codes anddistance � surface codes in the Sycamore superconducting qubit

architecture. Using repetition codes, we demonstrate exponential

suppression of bit or phase errors with ���x reduction in error rate from d=�
to d=��, even after �� rounds of measurement. We also show that ourdevice is well described by a simple depolarizing error model, allowing us toproject the performance of larger codes. The exponential suppression oferror and validation of theoretical assumptions about the behavior of errors
provides further evidence that surface codes with superconducting qubits
are a viable path towards a fault tolerant quantum computer.

033

CP-02-03

Two-dimensional array of superconducting
qubits with vertical accessYasunobu Nakamura
RIKEN Center for Quantum Computing

Abstract
Superconducting circuits are one of the most promising platforms forquantum computing. With the rapidly improving ﬁdelities of the control
gates and readouts, more and more advanced computation becomesachievable. There are a few diﬀerent architectures under intensive studies,roughly classiﬁed with tunable-frequency or ﬁxed-frequency qubits andwith tunable or ﬁxed couplings. The less tunability tends to lead the longer
coherence and less demands for wiring. On the other hand, the system

could be vulnerable to the device parameter ﬂuctuations in the fabrication
as well as the energy coincidences with two-level ﬂuctuators and theresidual interactions between neighboring qubits, causing a trade-oﬀ. In

this talk, we introduce our approach with a square lattice of ﬁxed-frequency
transmon qubits directly coupled with their nearest neighbors via

capacitors. The circuit is controlled and read out only through microwave
signals. To realize a tile-able design and mitigate the wiring issues in theplanar approaches, we bring the control and readout lines vertically to thechip. We report the progress on the design and characterization of the chips
and discuss the possible improvements and limitations.

034

CP-03-01

Silicon photonic quantum computing
Pete Shadbolt
PsiQuantum

Abstract
PsiQuantum is building the world’ s ﬁrst useful quantum computer using

silicon photonic chips to process quantum information with single photons.
This linear optical approach to quantum computing oﬀers highly coherent
qubits, high ﬁdelity single qubit gates, and probabilistic entangling

operations that can be implemented using well-known quantum opticalmethods. PsiQuantum’ s fusion-based quantum computing (FBQC)

architecture based on these operations has a very low optical depth andextremely high tolerance to optical loss. The key advantage of photonic

quantum computing is the fact that the required silicon photonic chips canbe mass manufactured in semiconductor fabrication facilities, allowing

scaling to achieve large-scale error correction. In this talk, we will show how
unique technology in the areas of silicon photonics and quantum systemarchitecture enable the path to large-scale, fault-tolerant, general-purpose
quantum computing.

035

CP-03-02

Large-scale fault-tolerant universal quantum
computing with quantum teleportation
Akira Furusawa
The University of Tokyo and RIKEN

Abstract
Time-domain multiplexed one-way quantum computing based on quantum
teleportation is a method to overcome various problems for the realizationof practical quantum computers, such as scalability, fault-tolerance, anduniversality. I will talk about our recent progress to this direction.

036

CP-04-01

Superconducting quantum- and digital-hybrid
computers - tackling of increasing wirings
Yutaka Tabuchi
RIKEN Center for Quantum Computing

Abstract
Quantum computing gains intensive attention to broad ﬁelds ofresearchers, people in the industry, governments, and many scientiﬁc fansall over the world. In RIKEN Center for Quantum Computing, we researchsuperconducting quantum computers by developing the quantum

computers themselves. Whereas we know that fundamental elements in

hardware include superconducting circuits fabricated on a silicon substrate,

packaging enclosure, wiring inside a cryostat, control electronics, and signal
processing circuits, a scalable organization of the elements for quantum
computers are in the research stage. Here, I focus on the I/O interface

between a chip and control electronics and discuss the scalable wiringarchitecture for a future goal. Having reconsidered current bottlenecks, we
ﬁnd that the uniformity of devices and quantum gates, exploits oftranslation symmetry in the surface code, and wiring hierarchization lead to
I/O bandwidth reduction. I will lastly introduce a stacked heterogeneousquantum module structure as an organization of quantum computers.

037

CP-04-02

The hybrid quantum circuitswith trapped electrons
Atsushi Noguchi
Komaba Institute for Science, The Univ. of Tokyo, Japan

Abstract
Electrons trapped in a vacuum by a Paul trap have the wonderful features ofa quantum system: fast operation, isolation from the environment, and aperfect two-level system. It is also possible to eﬃciently connect thediﬀerent traps using superconducting wires. The electron Paul traps haverecently been reported in room temperature system. On the other hand, theﬂoating electrons have no internal degrees of freedom to interact with light,
and cannot be controlled like ion trap systems, and have not yet beencooled to the ground state. In this talk, we will introduce our eﬀorts torealize the electron Paul trap quantum system.

038

CP-05-01

Quantum simulation with ytterbium atoms
in optical lattices
Shintaro Taie
Department of Physics, Kyoto University, Japan

Abstract
Ultracold atoms in optical lattices have been attracted much interest for its

application to quantum simulation. For their defect-free periodic potentials,
highly controllable kinetic and interaction energies and experimental

access to various physical quantities, optical lattices provide a unique

opportunity to simulate strongly correlated solid electrons, especially thosedescribed by the Hubbard model.

The SU(N) Hubbard model which is a simple extension of the spin SU(�)symmetry in the Hubbard model to general SU(N). The SU(N) Hubbard

model has long history of theoretical study such as large-N approach fordeeper understanding of the physically important SU(�) case, and simple
models for transition metals with orbital degeneracy. Recently SU(N)physics gained much more practical interests due to the possibility of its

quantum simulation with laser-cooled alkaline-earth-metal atoms, which

possess natural SU(N) spin symmetry due to the decoupling of nuclear spinfrom inter-atomic interactions.

In this talk, we present our experimental progress on simulating the SU(N)
Hubbard model with ultracold ytterbium atoms. Especially, we focus onshort-range antiferromagnetic behavior observed in optical lattices andthermometry performed by the detailed comparison with state-of-the-art
many-body theory.

039

CP-05-02

Ultrafast and ultracold quantum simulator/
computer with attosecond precision
Kenji Ohmori
Institute for Molecular Science, National Institutes of Natural Sciences

Abstract
Many-body correlations govern a variety of important quantum phenomena

including the emergence of superconductivity and magnetism in condensed
matter as well as chemical reactions in liquids. Understanding quantum

many-body systems is thus one of the central goals of modern sciences andtechnologies. Here we demonstrate a new pathway towards this goal bygenerating a strongly correlated ultracold Rydberg gas with a broadband

ultrashort laser pulse. We have applied our ultrafast coherent control withattosecond precision [�] to a strongly correlated Rydberg gas in an optical
dipole trap, and have successfully observed and controlled its ultrafast

many-body electron dynamics [�-�]. This new approach is now applied to an
atomic BEC, Mott insulator lattice, and arbitrary array assembled with

optical tweezers to develop into a pathbreaking platform for quantum
simulation and computation on the ultrafast timescale [�-�].

This project is in progress in tight collaboration with Hamamatsu Photonics
K.K..

040

CP-05-02

References[�] H. Katsuki et al., Acc. Chem. Res. ��, ���� (����).
[�] N. Takei et al., Nature Commun. �, ����� (����).

Highlighted by Science ���, ���� (����); IOP PhyscisWorld.com (����).

[�] C. Sommer et al., Phys. Rev. A ��, ������ (����).
[�] C. Liu et al., Phys. Rev. Lett. ���, ������ (����).

[�] M. Mizoguchi et al., Phys. Rev. Lett. ���, ������ (����).

[�] Patents (US: �rd. Nov. ���� and JAPAN: ��th Apr. ����)“Quantum simulator and quantum simulation method” ,H. Sakai (Hamamatsu Photonics K.K.), K. Ohmori (NINS) et al.

[�] UC Boulder / NIST Quantum Technology Website : CUbit Quantum Initiative
https://www.colorado.edu/initiative/cubit/newsletter/newsletter/june-����

“A metal-like quantum gas: A pathbreaking platform for quantum simulation”

041

CP-06-01

Engineering qubits in siliconwith atomic precision
Michelle Simmons
Silicon Quantum Computing, Sydney Australia

Abstract
The realisation of a large-scale error corrected quantum computer relies on
our ability to reproducibly manufacture qubits that are fast, highly

coherent, controllable and stable. The promise of achieving this in a highly
manufacturable platform such as silicon requires a deep understanding of
the materials issues that impact device operation. In this talk I will

demonstrate our progress to engineer every aspect of device behaviour inatomic qubits in silicon. This will cover the use of atomic precision
lithography to achieve fast, controllable exchange coupling, qubit

initialisation and read-out; high quality epitaxial growth to create all

epitaxial gate structures allowing for highly stable qubits; and unique

imaging and modelling techniques that provide a deep understanding of

the impact of the solid state environment on qubit designs and operation.

042

CP-06-02

Quantum computation - spins inside
Lieven M.K. Vandersypen
QuTech and Kavli Institute of Nanoscience, Delft University of Technology

Abstract
Quantum computation has captivated the minds of many for almost two
decades. For much of that time, it was seen mostly as an extremelyinteresting scientiﬁc problem. In the last few years, we have entered a newphase as the belief has grown that a large-scale quantum computer canactually be built. Quantum bits encoded in the spin state of individual

electrons in silicon quantum dot arrays, have emerged as a highly promising
direction. In this talk, I will present our vision of a large-scale spin-based

quantum processor, and ongoing work to realize this vision. This includes
two-qubit gate ﬁdelities of more than ��.�%, universal control of up to six
qubits, and the coherent coupling of spin qubits at a distance. Finally, inclose collaboration with Intel, we have fabricated and measured quantum

dots using all-optical lithography on ��� mm wafer, using industry-standard
processing, demonstrating excellent qubit performance. When combined,
the progress along these various fronts can lead the way to scalable
networks of high-ﬁdelity spin qubit registers for computation andsimulation.

043

CP-06-03

Si platform for spin-based quantum computing
Seigo Tarucha
Riken Center for Quantum Computing & Center for Emergent Matter Science

Abstract
Silicon is a promising platform for making spin qubits in quantum dots

(QDs), on the grounds of several advantages of a long intrinsic decoherencetime, a possible high-temperature operation, and compatibility in device
fabrication with industrial technology. One of the challenges indevelopment of Si quantum computing is to improve the control ﬁdelities ofsingle- and two-qubits beyond the quantum error correction threshold, ��% in the surface code. For the single qubits the ﬁdelity higher than ��.�%has been achieved but yet limited to �� % for the two-qubits. But very

recently a couple of reports on the two-qubit gate ﬁdelity above ��% haveappeared on arXiv.

In this work we use Si/SiGe triple quantum dots (TQDs) to operate two andthree spin qubits with high ﬁdelities. We apply a micro-magnet technique toincrease the single qubit drive and exchange control for two qubits in two

QDs of the TQD and ﬁnally achieve the two-qubit gate ﬁdelity above �� %.
Based on this result we develop three qubit operations for implementing
quantum error correction. We use the TQD to generate a three-spin

entangled state, called GHZ state, and a Toﬀoli gate and then demonstrate
the three-qubit phase error correction.

044

CP-07-01

Next-generation quantum annealing testbed
William Oliver
EECS, Physics, and Lincoln Laboratory, MIT, USA

Abstract
Quantum annealers based on superconducting ﬂux qubits have generated
signiﬁcant interest as a tool for solving complex optimization problems.

However, a demonstration of improved performance over the best knownclassical algorithms has remained elusive on existing quantum annealing

hardware. Hardware improvements such as longer qubit coherence times

and enhanced access to key control parameters may be central to achieving
a computational advantage. Under DARPA's Reversible Quantum Machine
Learning and Simulation (RQMLS) program, MIT Lincoln Laboratory is

responsible for operating a state-of-the art quantum annealing testbed.
This ﬂexible testbed is fabricated using a �D-integrated three-tierarchitecture. It contains �� high-coherence ﬂux qubits with high-bandwidth
individual ﬂux controls (��� MHz) and high-ﬁdelity readout. In thispresentation, we will provide an overview of the testbed design andoperation.

This research was funded in part by the Oﬃce of the Director of National
Intelligence (ODNI), Intelligence Advanced Research Projects Activity(IARPA) and the Defense Advanced Research Projects Agency (DARPA) under
Air Force Contract No. FA����-��-D-����. The views and conclusions

contained herein are those of the authors and should not be interpreted asnecessarily representing the oﬃcial policies or endorsements, either

expressed or implied, of the ODNI, IARPA, DARPA, or the U.S. Government.

045

CP-07-02

Algorithmic breakeven in quantum annealing
Daniel Lidar
Departments of Electrical and Computer Engineering, Chemistry,
and Physics, University of Southern California, USA

Abstract
As quantum computing proceeds from perfecting physical qubits towards

testing logical qubits and small scale algorithms an urgent question being
confronted is how to decide that critical milestones and thresholds havebeen reached. Typical criteria are gates exceeding the accuracy thresholdfor fault tolerance logical qubits with higher coherence than the constituent
physical qubits and logical gates with higher ﬁdelity than the constituent
physical gates. In this talk I will argue in favor of a diﬀerent criterion I call"quantum algorithmic breakeven" which focuses on demonstrating analgorithmic scaling improvement in an error-corrected setting over theuncorrected setting. I will present evidence that current experiments withcommercial quantum annealers have already crossed this threshold. I will

also discuss our latest evidence for a “limited quantum speedup” with suchdevices, and the need to explore alternatives to the traditional setting of
adiabatic, “forward” quantum annealing.
References:

T. Albash, D. Lidar, PRX �, ������ (����)A. Pearson, A. Mishra, I. Hen, D. Lidar npjQI � ��� (����)E.J. Crosson, D. Lidar, Nat. Rev. Phys. (����)046

CP-08-01

Fault-tolerance with bosonic qubits
Shruti Puri
Yale University

Abstract
Recently a new paradigm of quantum computing has gained momentum inwhich a qubit is encoded in non-classical states of a quantum oscillator.

Such qubits are known as continuous-variable or bosonic qubits and theirprimary advantage is that they can be made robust against certain sourcesof noise by design or by active error correction directly to the physicaloscillator mode. I will discuss recent advances in the development ofbosonic qubits in the circuit-QED platform and show how their inherent

properties can be leveraged for hardware-eﬃcient fault-tolerant quantum
computation.

047

CP-08-02

Fault-tolerant quantum computation inwith 3D cluster states
Robert Raussendorf
University of British Columbia, Canada

Abstract
I discuss fault-tolerant quantum computation in the presence of geometricconstraints, speciﬁcally fault-tolerant measurement-based quantum
computation on �D cluster states, and its two-dimensional circuit

counterpart based on the surface code. After reviewing some backgroundon measurement-based quantum computation and fault-tolerance, I

discuss the inherent quantum error-correction capability of �D cluster
states, and its topological origin. I then describe how to implement

topologically protected quantum gates in this setting. I conclude with adescription of recent advances on the theory frontier, and a summary of thestatus of experiment.

048

CP-09-01

Beyond NISQ / Toward FTQC Panel Discussion
Masato Koashi
Univ. of Tokyo

Abstract
While we are about to enter the era of quantum computers with a few
hundreds of qubits with Noisy Intermediate-Scale Quantum (NISQ)

technology, it is also necessary to endeavor after fault-tolerant (FT)architecture in order to build a quantum computer of much larger scale andto beneﬁt from the full potential of quantum computation. The panel will
discuss future directions of research to achieve such a goal of FTQC
technology.

049

CP-10-01

Provably accurate simulation of gauge theories
and bosonic systems
Yuan Su
GoogleAbstract
Quantum many-body systems involving bosonic modes or gauge ﬁelds haveinﬁnite-dimensional local Hilbert spaces which must be truncated toperform simulations of real-time dynamics on classical or quantum

computers. To analyze the truncation error, we develop methods forbounding the rate of growth of local quantum numbers such as theoccupation number of a mode at a lattice site, or the electric ﬁeld at a latticelink. Our approach applies to various models of bosons interacting with

spins or fermions, and also to both abelian and non-abelian gauge theories.
We show that if states in these models are truncated by imposing an upper
limit Λ on each local quantum number, and if the initial state has low local

quantum numbers, then an error at most ε can be achieved by choosing Λ toscale polylogarithmically with �/ε, an exponential improvement overprevious bounds based on energy conservation. For the Hubbard-Holsteinmodel, we numerically compute a bound on Λ that achieves accuracy ε,obtaining signiﬁcantly improved estimates in various parameter regimes.

We also establish a criterion for truncating the Hamiltonian with a provableguarantee on the accuracy of time evolution. Building on that result, weformulate quantum algorithms for dynamical simulation of lattice gauge

theories and of models with bosonic modes; the gate complexity depends

050

CP-10-01

almost linearly on spacetime volume in the former case, and almost

quadratically on time in the latter case. We establish a lower bound showingthat there are systems involving bosons for which this quadratic scaling
with time cannot be improved. By applying our result on the truncation
error in time evolution, we also prove that spectrally isolated energy

eigenstates can be approximated with accuracy ε by truncating local
quantum numbers at Λ=polylog(�/ε).

051

CP-10-02

Quantum algorithms for large-scale problems
François Le Gall
Graduate School of Mathematics, Nagoya University, Japan

Abstract
In view of the signiﬁcant progress made on the hardware side of quantum
computing, unravelling the potential of large-scale quantum computers,

and especially discovering compelling applications that can justify the hugeamount of eﬀort, time and investments needed in the next decades for theirdevelopment, is a pressing issue. In this talk I will give an overview of thevibrant research ﬁeld of quantum algorithms for large-scale quantum

computers. I will in particular discuss exciting recent developments, such as
quantum algorithms for string problems with potential applications tobioinformatics, quantum algorithms for graph problems with potential

applications to big data, and quantum algorithms for algebraic problems
such as matrix multiplication and eigenvalue estimation.

052

CP-11-01

Promises and challenges of variational
quantum algorithms
Patrick Coles
LANL

Abstract
Beyond ﬁnding ground states, new applications have recently emerged for
Variational Quantum Algorithms (VQAs). These include dynamical

simulation, metrology, solving linear systems, and principal component
analysis, among others. Moreover, new tools are making VQAs morefeasible, such as quantum-aware optimizers and error mitigation methods.
VQAs also exhibit an intriguing resilience to certain types of noise. Thesesigns point to VQAs soon providing quantum advantage for practicallyinteresting problems. On the ﬂip side, new analytical results have studied
the gradient scaling for VQAs. These results paint a concerning picture,and show that barren plateaus in the training landscape will emerge if care
is not taken. Barren plateaus are caused by lack of structure or simply by

the presence of noise. Avoiding barren plateaus has now become a crucial
area of research. This talk will review both the exciting and challenging
nature of VQAs for near-term quantum computing.

053

CP-11-02

Development of quantum machine learningalgorithms and experimental realization
Kosuke Mitarai
Graduate School of Engineering Science, Osaka University/
QIQB Center, Osaka University/ JST PRESTO

Abstract
Applying quantum computers to machine learning tasks is an exciting newarea of research. In this talk, I will ﬁrst present our experimental

demonstration of a quantum machine learning algorithm called quantum
kernel method. Using an NMR quantum simulator, we successfully

employed ~�� qubits for machine learning tasks. Secondly, I will present analgorithm called a quantum recurrent neural network, which is an extensionof the classical recurrent neural network to a quantum setting. Its algorithm
details and properties will be discussed.

054CP-12-01

Toward realization of quantum error correction
and fault-tolerant quantum computing
Keisuke Fujii
Graduate School of Engineering Science, Osaka Univ., Japan

Abstract
Now that ��-��� qubit scale quantum computers have been realized, thenan experimental demonstration of quantum error correction is becoming areality. In this talk, I will present a result of simulation of quantum error
correction on the scale of �� qubits under a realistic noise model.

Speciﬁcally, we will discuss what physical conditions are required to extend
the lifetime of logical qubits against the coherence time of physical qubits.

In the post-NISQ era, it is required to evaluate the performance of quantum
error correction on the scale of ���� qubits. For such a situation, we willshow that it is possible to simulate quantum error correction over ����qubits by using a quasi-probability method, taking advantage of the factthat most of the quantum circuits employed in quantum error correction

are Cliﬀord. Furthermore, by applying quantum error mitigation, which wasdeveloped as a method to overcome the noise problem in NISQ devices, toquantum error correction, the number of required physical qubits can begreatly. We expect that these researches will make an important

contribution to the evolution from the NISQ era to the FTQC era closing
their gap.

055

CP-13-01

Break down the high-order tensors of quantum
chemistry, for O(N)-depth circuit algorithm
Yuki Kurashige
Department of Chemistry, Graduate School of Science, Kyoto University

Abstract
Quantum chemistry is gaining more attention as a promising ﬁeld of

application of quantum computers because of its high aﬃnity to the qubit
representations and universal gate operations. Even so, the status is far

from real-world applications. One of the reasons is that high-order tensors
that describe electron interaction or correlation, e.g., the two-electron

molecular integrals or double-excitation cluster amplitudes, need to beprocessed in quantum chemical calculations, which will be interpreted by atleast O(N^�) quantum gates in the circuits, thereby making it infeasible on
current and near-term quantum computers. Here, we present an eﬃcienttensor decomposition for the above high-order tensors, and a new ansatz
for the variational quantum eigensolver. The method is able to be

implemented with O(N)-depth quantum circuit and at the same time
considerably reduce the required number of measurements.

056

CP-13-02

Quantum computing for chemistry
Markus Reiher
Lab. f. Phys. Chem., ETH Zurich, Switzerland

Abstract
Five years ago, we discussed whether and how quantum computing may
contribute to the solution of actual chemical problems that are hard to

tackle with traditional means at the example of the nitrogenase enzyme[PNAS ��� (����) ����]. We have recently updated that study at anotherexample (a carbon dioxide ﬁxation catalyst), considering latest estimatesfor hardware timings and algorithmic advances [Phys. Rev. Res. � (����)������]. A main result of these eﬀorts, which always target the exact

many-particle wave function, has been that quantum computing may

indeed become a game changer in the not too distant future. Accordingly,

we proceeded to present a more general discussion of a potential quantum
advantage in the molecular sciences in a perspective article[arXiv:����.�����], which ponders the many aspects of a quantum

computation in comparison to competing traditional methods (see, e.g., thedensity matrix renormalization algorithm as an example [J. Chem. Phys. ���(����) ������]). Apart from error-controlled exact-diagonalization

solutions, more approximate parametrization obtained, for example, withthe variational quantum eigensolver are also advantageous (see, forinstance, our contribution to this ﬁeld regarding vibrational spectroscopy[Chem. Sci. �� (����) ����]). In my talk, I will review our work of the past
years and present an outlook to future work.

057CP-14-01

Improving adiabatic quantum computing
with non-adiabatic methods
Wolfgang Lechner
University of Innsbruck

Abstract
The speed of adiabatic processes, and thus adiabatic quantum computing isfundamentally limited by the adiabatic theorem. Counter-diabatic driving isa method that introduces additional time-dependent Hamiltonian terms inorder to suppress diabatic transitions. However, these terms are highly
non-local in many-body systems and thus not practical for near term

applications. Recently, approximations for counter-diabatic terms havebeen introduces which oﬀer a trade-oﬀ between complexity of theimplementation and gain in ground-state ﬁdelity. I will discuss the simplest
approximations of single and two-body counter-diabatic terms.

058

Abstract

PL
TracksPlenary Sessions
Contents / Topics

Welcome from Organizing Committee and Hosting
Ministries, Plenary Talks, Keynote Speeches

CP
TracksQuantum Computing Track
Contents / Topics

Quantum Computing with Atoms and Ions,

Superconducting Quantum Computers(QC),
Photonic QC,Young Researcher

Session, Quantum Simulations, Semiconductor QC,

Quantum Annealing Toward FTQC(Tutorial), Beyond
NISQ/Toward

FTQC Panel Discussion,Quantum Architechture,

Quantum Algorithms, NISQ Algorithms,Quantum
Algorithms for Chemistry

CC

SE

TracksTracksQuantum Cryptography &Quantum Sensing Track

Communication Track
Contents / Topics

Contents / Topics

Technologies of Field and Satellite QKDs), Challenges forLife Sciences, Quantum Sensors and Quantum Life

Quantum Internet, Quantum Cryptography(Up-to-date
Quantum Technology

Platform (QKD Networks, Satellite QKD and theirintegration), Industry Panel, Young Researcher Session**CC-�� on �th and CC-��, CC-�� on �th Dec aresupported by SIP (cross-ministerial Strategic Innovation
promotion Program).

Solid-State Quantum Sensors, Quantum Sensors for
Sciences, AtomInterferometer, Cold Atom, Atomic/Ion Clocks, Short
Presentations by Young Researchers*�th Dec Sessions are a joint-program with The �th
IFQMS (The �th International Forum on Quantum
Metrology and Sensing).

059

CC-01-01

Bringing QKD to real-world digital infrastructures
Michele Mosca
evolutionQ, and IQC, University of Waterloo, Canada

Abstract
For the advent of large-scale fault-tolerant quantum computers to

represent a positive milestone in human history, we must ﬁrst evolve critical
digital infrastructures to be safe from quantum-enabled attacks.

However, the current status quo in cryptography is already not goodenough anymore. With connected industrial devices, driverless cars, �G, andmore, the stakes are already far higher than they were a decade or moreago, and they keep getting higher.

The emerging “quantum internet” further ampliﬁes the positive impacts ofquantum computation and quantum sensing, and also oﬀers afundamentally new suite of tools for protecting digital platforms from a

range of cyber attacks. Quantum key establishment (known as Quantum
Key Distribution, QKD) is one such tool that is already commerciallyavailable and will continue to improve as quantum technologies continue toadvance.

It is already time to design QKD into real-world digital infrastructures,alongside other quantum-safe methods. I will overview our work facilitating
robust scalable real-world deployment of QKD.

060

CC-01-03

Ion-photon interface for quantum networks
Hiroki Takahashi
Okinawa Institute of Science and Technology

Abstract
The complementary beneﬁts of trapped ions and photons as carriers ofquantum information make it appealing to interface them via cavity QED.
In particular a quantum register made of a string of ions and interfaced

eﬃciently with optical photons provides an excellent platform for quantum

repeaters and quantum networks. With this objective in mind, we have beenworking on the integration of micro optical cavities in ion traps. In the talk,we will present our achievements so far and future prospects.

061

CC-01-04

Designing tomorrow’ s quantum internet
William John Munro
NTT Basic Research Laboratories, Japan

Abstract
Tomorrow’ s quantum internet will rely on the transmission of quantum
signals over long distances that can be used to support many tasks

including quantum communication, quantum remote sensing and even
distributed quantum computation. The performance of such along-distance network will be severely aﬀected by channel losses between

the network’ s users. Quantum repeaters are one solution to this issue but a
key question is how to generate the required long-range entanglement

eﬃciently. In this talk we will take a top-down architectural approach to
explore how the various kinds of quantum repeaters may operate in the

future and estimate their performance in a network environment. We willshow that the architectural network design will have a profound impact on
the network’ s performance highlighting how it is critical that both thequantum and classical signals are integrated together. Further we will

explore circuit, packet and quantum switched networks discussing what

constraints they put on the form of the quantum repeaters noting that not
all repeater designs allow all the network modes.

062

CC-03-01

Quantum Internet: from classicalto quantum paths
Angela S. Cacciapuoti
Department of Electrical Engineering and Information Technology,
University of Naples Federico II, Italy

Abstract
Generally, in a quantum network, the information carriers are treatedquantum mechanically, but the paths through which they propagate arestill classical, obeying the laws of classical causality. But this assumption

can be generalized such as, not only the information or the channels, butalso the placement of the channels ‒ i.e., the paths along with the carriers

propagate ‒ can be quantum. This unconventional placement of channels

has been theoretically and experimentally veriﬁed, and it has been provento be able to describe powerful setups for the transmission of both classicaland quantum information. This genuine quantum phenomenon plays aparamount role for achieving unprecedented information transfer

capacities, and it must be fully understood and harnessed for the Quantum
Internet design.

063

CC-03-02

Software and protocol stacks
for quantum networks
Wojciech Kozlowski
QuTech, Delft University of Technology, the Netherlands

Abstract
The second quantum revolution brings with it the promise of a quantum
internet. As research eﬀorts move beyond basic demonstrations offundamental physics new challenges emerge in the ﬁeld of system design
and implementation of quantum networks. For example, scaling current
quantum communication experiments to a global quantum internet will

also require platform-independent programmability and robust automation
capabilities. A new ‒ quantum ‒ software and network protocol stack need

to be developed for this purpose. In this talk I will present our eﬀorts on theﬁrst ever implementation of a link and physical layer protocol onstate-of-the-art solid-state quantum networking nodes. The physical layer
protocol provides a best-eﬀort service for entanglement generation

attempts and the link layer protocol abstracts that into a robust andplatform-independent entanglement generation service. We evaluate our
implementation by running a full state tomography of the delivered

entangled states, as well as preparation of a remote qubit state on a server

by its client. Our results mark a clear transition from physics experiments toquantum communication systems, which will enable the development andscaling of future quantum networks.

064

CC-03-03

Genuine and optimized entanglement-based
quantum networks
Wolfgang Duer
University of Innsbruck, Austria

Abstract
We consider entanglement-based quantum networks, where pre-sharedmultipartite entangled states -that can be generated prior to any network

request- serve as a resource to fulﬁll general network requests on demand.
This oﬀers new possibilities and features such as speeding up network

requests, and network optimization independent of the underlying physicalstructure. The main challenge is to identify suitable resource states shared
between network devices that can be stored, and then modiﬁed by local

means such that the desired output state (and hence the desired network

functionality) can be guaranteed. This minimizes generation times for target
states, and allows for optimizing network structures that are independentof the underlying physical network topology. We show how to design andoptimize such entanglement-based networks, and demonstrate a storage
advantage when using multipartite entangled states. Finally, we discuss

how to make quantum networks genuine quantum by providing them withthe possibility of handling superposed tasks and superposed addressing via
a quantum control register. This allows one e.g. to prepare superposition of
diﬀerent target states, or to send information among a superposition of
diﬀerent paths.

065

CC-03-04

Quantum physical unclonable functions
and their comprehensive cryptanalysis
Elham Kashefi
CNRS Sorbonne Universite and University of Edinburgh

Abstract
A Physical Unclonable Function (PUF) is a device with unique behaviour thatis hard to clone due to the imperfections and natural randomness during
the manufacturing procedure, hence providing a secure ﬁngerprint. A

variety of PUF structures and PUF-based applications have been exploredtheoretically as well as being implemented in practical settings. Recently,

the inherent unclonability of quantum states has been exploited to derive
the quantum analogue of PUF as well as new proposals for the

implementation of PUF. In this talk, we present the ﬁrst comprehensive

study of quantum Physical Unclonable Functions (qPUFs) with quantum

cryptographic tools, introducing a new quantum learning attack that can

explore the vulnerabilities of quantum and certain classical PUFs leading to

general no-go results on the unforgeability of qPUFs. On the other hand, we
prove that a large family of qPUFs (called unitary PUFs) can provide

quantum selective unforgeability which is the desired level of security formost PUF-based applications. Moreover, we elaborate on the connection

between qPUFs as hardware assumptions, and computational assumptions
such as quantum pseudorandomness in order to establish the link between
these two relatively new ﬁelds of research.

066

CC-03-05

Entanglement based quantum networking
Siddarth K. Joshi
Unversity of Bristol

Abstract
Quantum communication is inherently a two party point to point protocol.
Its information theoretically perfect security depends on the physicalimpossibility of exactly duplicating individual quantum states. However,this very property also makes long distance and network based

implementations very diﬃcult. This is because Information cannot be readand then resent without compromising the security of the quantum
network.

Multiplexed distribution of entanglement allows the simple and scalable

distribution of bipartite entangled states to all pairs of multiple users. The

users can then perform measurements on these states to implement many
protocols including Quantum Key Distribution, Anonymous protocols,
Digital Signatures, Secure Initial Authentication Transfer and network
ﬂooding. We present the experimental implementation of all these

protocols on our �-user city wide quantum network using deployed telecom
infrastructure. Lastly we present preliminary data on how we can extend
this type of quantum network over even longer ﬁbre distances of up to
��km.

067

CC-04-02

OpenQKD use-case demonstrations in Europe
Andreas Poppe
Center for Digital Safety & Security, AIT Austrian Institute of Technology, Austria

Abstract
In this talk I will brieﬂy update the status of the ongoing European initiative
to bring QKD to the ﬁeld. Testbeds will be installed at �� diﬀerent sites

distributed over EU, Switzerland and UK with more than �� commercial

QKD-systems involved. Thereby deployments relevant to future use-cases

have already been demonstrated and I will also point to some future workof the �� partners.

068

CC-04-03

Lessons from the SpooQy-1 satellite
Alexander Ling
Centre for Quantum Technologies, National University of Singapore, Singapore

Abstract
SpooQy-� was a nanosatellite developed by the Centre for Quantum

Technologies (Singapore) to demonstrate entanglement generation in

space, as a pathﬁnder for more ambitious satellite to ground experiments.
The satellite was deployed in June ����, and spent �� months fully

operational in low Earth orbit before burning up on re-entry. I will review
some of the major results and data that have been collected over the
lifetime of the satellite and discuss how it will guide future in-orbit
demonstrations and experiments.

069

CC-04-04

High-level concepts and design of commercial
satellite-based QKD networks
Manuel Erhard
Quantum Technology Laboratories [qtlabs] GmbH, Austria

Abstract
Quantum Key Distribution (QKD) is a fast-growing scientiﬁc but today

primarily commercial ﬁeld. Governments and private businesses seekenhanced security solutions that can withstand future hacking attacks

directed against public key encryption systems. Today, many diﬀerent QKD

protocols claim to oﬀer “unconditional” security. However, looking in moredetail, many subtleties lead to diﬀerent security levels, or in worst-casescenarios, to no security at all. Thus, it is essential to appropriately selectand design QKD protocols and networks suitable for intercontinental
long-distance satellite-based QKD networks. This talk presents andcompares diﬀerent QKD protocols concerning their security, key-rate

performance, and applicability, especially for satellite-based QKD networks.
Our focus lies in high-level mission planning parameters, such as orbitalheight, number of satellites per orbit, and realistically achievable secret key
rates with various QKD protocols and technologies. Finally, we present
simulation results of various case studies ranging from European tointercontinental use-cases.

070

CC-04-05

Quantum networking research at Los Alamos
Raymond Newell
Los Alamos National Laboratory, USA

Abstract
The value of a classical network, deﬁned as the number of uniqueconnections possible, scales as the square of the number of connected

users (Metcalfe’ s law). In contrast, for quantum networks with quantum

resources, such as computers and sensors, the computational power of the
network scales exponentially in the number of connected nodes, making aquantum network of quantum devices much more capable than a classicalnetwork of the same size.

Quantum networks will require eﬃcient sources of indistinguishable single

photons on demand to create ancilla photons for quantum error correctionof multi-qubit quantum error correcting codes. Existing technologies
currently face several challenges: output photons are often easily

distinguishable; wavelengths are often not compatible with standard

telecom optical ﬁber; and emission is often omnidirectional, making itdiﬃcult to couple into ﬁber. We will review our eﬀorts to create defects insingle-wall carbon nanotubes (SWCNT) via covalent chemicalfunctionalization to emit a stream of single photons at a telecom
wavelengths. Our existing SWCNT devices yield ��% photon

indistinguishability and we have realized telecommunications C-band

photon emission as well as high-eﬃciency coupling into ﬁber. We plan todevelop these devices for integration with quantum communication links insupport of large-scale quantum networks.

071

CC-04-06

Fundamentally applied quantum communication
Rob Thew
University of Geneva

Abstract
We present several aspects of our work on quantum communication

ranging from next generation quantum repeaters and multipartite systems
to QRNG and QKD development. We will touch on the connection between
fundamental research and applied development of quantum

communication devices and systems, in particular, exploiting concepts
from Bell and nonlocality to make these “better” , as well as theimportance of integrated photonics.

072

CC-04-07

Finite-key security of continuous-variable
quantum key distribution
Masato Koashi
Univ. of Tokyo

Abstract
The security of quantum key distribution is often proved in the asymptotic

regime, but in order to establish security for an actual implementation, one
needs to prove it in the ﬁnite-key regime where the communication time is

ﬁnite. Although a conventional approach to the security using phase errors

in qubits excels in dealing with ﬁnite-size statistics, the use of qubits limited
its use to discrete-variable QKD protocols with photon detectors until

recently. Here I will explain how we can apply this approach to a two-statecontinuous-variable QKD protocol with homodyne/heterodyne detection toprove its ﬁnite-key security against general attacks.

073

CC-05-01

Overview of Japanese project “SIP”
and quantum secure could technologies
Masahide Sasaki
Quantum ICT Collaboration Center, NICT, Japan

Abstract
We present quantum secure cloud technologies which protect critical data
securely for a long time with high availability, and provide near optimal
computing services with quantum-classical hybrid solvers in a securemanner.

To realize these functions, we have integrated QKD, secret sharing,post-quantum cryptography, secret computing, as well as codesign

middleware for getting various quantum and classical computers work

together. We overview current status of deployment and standardization ofquantum secure cloud.

074

CC-05-02

Secure information society using"Quantum Secure Cloud"Mikio Fujiwara
Quantum ICT Laboratory, Advanced ICT Research Institute,
National Institute of Information and Communications Technology, Japan

Abstract
We have developed a system that implements a secret sharing protocol on aquantum cryptography network and enables secure transmission, storage,
and secondary use of data. We named the system as “a Quantum Secure

Cloud” . We are promoting a proof of concept (POC) in various ﬁelds. Thissystem not only handles electronic medical record data and genome

analysis data as data that requires conﬁdentiality for a long period of time,
but is also expanding into the ﬁnancial ﬁeld. We have developed an
exclusive OR-based high-speed secret sharing and high-speed OTP

cryptographic transmission system to support distributed backup of large

volumes of data. We were able to complete a distributed backup of a large
volume of ��GB of genomic data within �� hours. Furthermore, regarding
the secondary use of secure data (genomic data), a secret calculation

system assuming a trusted server is installed in the quantum secure cloud,and the trusted server restores the data only at the time of calculation andencrypts the system at the time of input / output. developed. This system isalso equipped with a ﬁltering function to prevent unnecessary leakage of
personal information. We will introduce other POCs as well.

075

CC-05-03

Quantum key distribution researchand development in NEC
Junichi Funada
NEC Technology Synergy Creation Division

Abstract
Quantum cryptography is a cryptographic method that can protect

information in the ultra-long term without the risk of being deciphered in

the future, and is expected to be applied to many important mission-criticalsystems. NEC is engaged in various research and development toward thecommercialization of quantum key distribution.

This presentation ﬁrst shows overview of NEC's QKD related activities, thenintroduction of CV-QKD research and ﬁeld trials of QKD. CV-QKD method canbe used over existing optical ﬁbers and is expected to be inexpensively

implemented. NEC and the partners are developing CV-QKD prototype andproceed evaluation. NEC and the partners also conduct ﬁeld trials of QKD insome important application areas.

076

CC-05-04

QKD R&D and field trials in Toshiba
Yoshimichi Tanizawa
Corporate R&D Center, Toshiba Corporation, Japan

Abstract
Quantum key distribution (QKD) provides a means for exchanging

cryptographic keys, the security of which makes no assumptions about anadversary's computing power or technological capability. This presentationshows R&D activities including high speed, long distance, and stable
operation of QKD, as well as a key delivery API for the QKD network

environment. It also shows various kinds of ﬁeld trials of QKD system and
QKD network conducted by Toshiba and the partners.

077

CC-05-06

Quantum communication activities in Canada
Norbert Lütkenhaus
Institute for Quantum Computing and Department of Physics and Astronomy,
University of Waterloo, Canada

Abstract
Canada has a strong background in quantum communication. In addition to
the experimental activities (see presentation of Thomas Jennewein) there

is a broad theory landscape in Canada that covers researchers in places like
Montreal, Ottawa, Toronto, Waterloo and Calgary. The theory researchdeals with groundwork of handling side-channels of QKD, QKD networks

and also applications beyond QKD. We are also leading a number of open
source platforms , including a project for post-quantum cryptography(openquantumsafe.org), QKD network stack (openQKDnetwork.ca) and thenumerical security evaluation of QKD (openQKDsecurity.org). The spectrumof activities range from academia to industry, with the quantum industry
coming together in the Quantum Industry Canada consortium.

078

Abstract

PL
TracksPlenary Sessions
Contents / Topics

Welcome from Organizing Committee and Hosting
Ministries, Plenary Talks, Keynote Speeches

CP
TracksQuantum Computing Track
Contents / Topics

Quantum Computing with Atoms and Ions,

Superconducting Quantum Computers(QC),
Photonic QC,Young Researcher

Session, Quantum Simulations, Semiconductor QC,

Quantum Annealing Toward FTQC(Tutorial), Beyond
NISQ/Toward

FTQC Panel Discussion,Quantum Architechture,

Quantum Algorithms, NISQ Algorithms,Quantum
Algorithms for ChemistryCC
TracksQuantum Cryptography &Communication Track
Contents / Topics

SE
TracksQuantum Sensing Track
Contents / Topics

Quantum Internet, Quantum Cryptography(Up-to-date

Solid-State Quantum Sensors, Quantum Sensors for

Quantum Technology

Sciences, AtomTechnologies of Field and Satellite QKDs), Challenges for
Platform (QKD Networks, Satellite QKD and theirintegration), Industry Panel, Young Researcher Session**CC-�� on �th and CC-��, CC-�� on �th Dec aresupported by SIP (cross-ministerial Strategic Innovation
promotion Program).

Life Sciences, Quantum Sensors and Quantum LifeInterferometer, Cold Atom, Atomic/Ion Clocks, Short
Presentations by Young Researchers*�th Dec Sessions are a joint-program with The �th
IFQMS (The �th International Forum on Quantum
Metrology and Sensing).

079

SE-01-01

Quantum sensing of quantum materials using
NV center microscopy
Amir Yacoby
Harvard University

Abstract
The magnetic ﬁelds generated by spins and currents provide a uniquewindow into the physics of correlated-electron materials and devices.

Proposed only a decade ago, magnetometry based on the electron spin of

nitrogen-vacancy (NV) defects in diamond is emerging as a platform that is
exceptionally suited for probing condensed matter systems. It can be

operated from cryogenic temperatures to above room temperature, has adynamic range spanning from DC to GHz, and allows sensor-sample
distances as small as a few nanometers. As such, NV magnetometry

provides access to static and dynamic magnetic and electronic phenomena
with nanoscale spatial resolution. While pioneering work focused on

proof-of-principle demonstrations of its nanoscale imaging resolution andmagnetic ﬁeld sensitivity, now experiments are starting to probe thecorrelated-electron physics of magnets and superconductors and to explore
the current distributions in low-dimensional materials. In this talk, I will

review some of our recent work that uses NV center magnetometry to image
skyrmions in thin magnetic ﬁlms, measure the spin chemical potential inmagnetic insulators, and image hydrodynamic electron ﬂow inlayered materials. In addition I will describe the use of NV centers in a new
scattering platform that uses spin waves as the probing excitation.

080

SE-01-02

Current status and prospects of solid-state
quantum sensors for Quantum-LEAP
Mutsuko Hatano
Tokyo Institute of Technology

Abstract
Solid-state quantum sensors using diamond and SiC are expected to havevarious applications due to their principle possibilities such as wide-ﬁeld

dynamic range, operating temperature range, and high special resolution
down to the atomic level.

In the MEXT Q-LEAP Quantum Solid-state Flagship Project, ﬁve companies,
ﬁve academia, and two national research institutes have teamed up to

develop a solid-state quantum sensor from basic science and technologies

such as materials and quantum protocols to sensor modules and application
prototypes.

In this talk, I would like to introduce the latest research topics of Q-LEAP,
such as high precision simultaneous measurement of current andtemperature in EV batteries, high-resolution magnetocardiographic imaging
of rats, probing into living cells by tip-type NV sensor. In addition,

expectations for a future "quantum leap" society based on quantum
solid-state sensor technology will be discussed.

This work was supported by MEXT Quantum Leap Flagship Program (MEXT
Q-LEAP) Grant Number JPMXS����������.

081

SE-01-03

Nanoscale vector AC magnetometry witha single nitrogen-vacancy center in diamond
Paola Cappellaro
Nuclear Science and Engineering, Physics Departments,
Massachusetts Institute of Technology, USA

Abstract
Detection of AC magnetic ﬁelds at the nanoscale is critical in applications
ranging from fundamental physics to materials science. Isolated

nitrogen-vacancy centers in diamond can achieve the desired spatial

resolution with high sensitivity. Still, vector AC magnetometry currently
relies on using diﬀerent orientations of an ensemble of sensors, withdegraded spatial resolution. Here I will present a novel protocol that

exploits a single NV to reconstruct the vectorial components of an AC
magnetic ﬁeld, by tuning a continuous driving to distinct resonanceconditions. As an experimental proof-of-principle, I’ ll show how to map the
spatial distribution of an AC ﬁeld generated by a copper wire on the surfaceof the diamond.

The proposed protocol combines high sensitivity, broad dynamic range,and sensitivity to both coherent and stochastic signals, with broad
applications in condensed matter physics.

082

SE-01-04

Planetary magnetic field sensing via electricalreadout of quantum centers in SiC
Corey J. Cochrane
Jet Propulsion Laboratory, California Institute of Technology, United States

Abstract
The most widely used magnetometers for scientiﬁc missions to space are
ﬂuxgate and optically-pumped atomic-gas instruments due to their highsensitivity, reliability, and proven performance. Fluxgates are simple androbust while the atomic-gas designs are highly accurate and stable.

However, it is very diﬃcult to include all of these desired speciﬁcations in asingle package with adequate size and power constraints for smaller

scientiﬁc missions that involve cubesats. This opens the door for infusion of

next-generation magnetometer technologies. In this work, we report on thedevelopment of a silicon carbide magnetometer, promising to be a low

complexity, lightweight, low power, and inexpensive alternative to these

heritage technologies. It measures magnetic ﬁeld induced changes in spin

dependent recombination (SDR) current within a pn junction. The change in
SDR current arises from the interaction of external magnetic ﬁelds with theatomic-scale defects in the SiC semiconductor. This change in current canbe detected electrically via magnetoresistance caused by zero-ﬁeld levelcrossings or low-ﬁeld electrically-detected magnetic resonance, thereby

giving the instrument the ability to self-calibrate, a signiﬁcant advantage inthe remoteness of space. The material properties of SiC, namely radiationand temperature hardness, are also very attractive for space applications inharsh environments.

083

SE-02-01

Production of color centers in nanodiamond
Olga A. Shenderova
Adámas Nanotechnologies, United States

Abstract
Diamond particles containing ﬂuorescent color centers provide combinationof outstanding photostability, sensitivity of ﬂuorescence to external stimuli
and excellent biocompatibility attractive for life science applications. Until
recently, however, the ﬂuorescent color palette of N-based centers was

restricted to particles emitting only in red or green, based on NV centersproduced in type Ib synthetic diamond, or NVN centers produced in type Ia
natural diamond, correspondingly. Limited color options impacts

applications of ﬂuorescent nanodiamonds (FND) in multiplexed biologicalimaging. Here we report on a breakthrough method of production ofmulticolor diamond particulates using ultra-high temperature annealing(>���� ℃), which generates conditions for the formation of one-, two- andthree-atom nitrogen complexes with vacancies in electron irradiated type Ib
synthetic diamond, providing vibrant luminescence in the red (NV), green(NVN) and blue (N� centers) spectral ranges, correspondingly. Remarkably,
the ultra-high temperature treated particles containing NV centersdemonstrated improved magneto-optical properties and open routes for

multiplexed labeling combined with sensing when NV centers coexist with
NVN or N� centers within individual particles. Moreover, enhanced ��Coptical hyperpolarizability of the treated particles was also observed, which
advocates a new paradigm in dual-mode ﬂuorescence/magnetic resonanceimaging enabled by diamond contrast agents.

084

SE-02-02

Nitrogen-vacancy centers in nanodiamonds as
temperature sensors and immunoassay reporters
Huan-Cheng Chang
Institute of Atomic and Molecular Sciences, Academia Sinica, Taiwan

Abstract
The negatively charged nitrogen-vacancy (NV−) center in ﬂuorescent

nanodiamonds (FNDs) is a point defect with unique magneto-opticalproperties. It has found wide applications in frontier areas of science andmany new innovations are emerging. Here, we present two new

applications of this quantum sensor: (�) FNDs embedded in polymer ﬁlms as
temperature sensing devices and (�) FNDs conjugated with antibodies as
immunodiagnostic reagents. In the ﬁrst task, we closely examined thetemperature dependence of the peak positions and heights of the zerophonon line of NV− centers in poly(�-hydroxyethyl methacrylate) ﬁlms from�� to ��� °C. A measurement sensitivity of better than �.� K Hz−�/� wasachieved over this temperature range. In the second task, we magneticallymodulated the ﬂuorescence intensities of NV− centers in FNDs. We achieved
selective detection of ��� nm FNDs on a highly ﬂuorescent nitrocellulose
membrane at a particle density of �.�� ng/mm� (or ~� × ���

particles/mm�). The utility and versatility of these techniques were

demonstrated with a study for the energy transfer kinetics of a resistively

heated gold microwire embedded in the ﬁlms as well as an application to
background-free detection of FNDs as reporters for lateral ﬂow
immunoassays.

085

SE-02-03

Treatment responses to immune checkpoint
inhibitor therapy evaluated by MRIShun Kishimoto
Radiation Biology Branch, NCI, USA

Abstract
Although immune checkpoint blockade (ICB) therapy has been widely used

as a promising treatment option, the evaluation for its eﬃcacy relies on thechange in tumor size, which can delay the clinical decision-making because
strong immune response often causes temporary tumor swelling called

pseudo-progression. Thus, developing new imaging approach to evaluate
the early physiological changes inside of the treated tumor is of great
importance. Our laboratory is equipped with Electron Paramagnetic

Resonance (EPR) scanner and hyperpolarized ��C MRI capable of in vivo
oximetry and metabolic imaging, respectively. By using these imaging
modalities as well as conventional �H MRI, we identiﬁed usefulfunctional/metabolic imaging biomarkers for early detection of thetherapeutic eﬀect of ICB therapy.

Anti-cancer eﬀect in parts of the body that were not the direct target of local
therapy is called abscopal eﬀect. Although abscopal eﬀect induced by local
radiation therapy is rarely observed, the occurrence is much higher whencombined with ICB treatment. We are investigating functional/metabolic

factors aﬀecting the occurrence of abscopal eﬀect by ICB+radiation therapy
in an ongoing study. The results from this study will also be presented.

086

SE-04-01

Quantum sensing enabled by spin qubits
in diamondFedor Jelezko
Institute of Quantum Optics, Ulm University

Abstract
Single nitrogen vacancy (NV) color centers in diamond currently have

suﬃcient sensitivity for detecting single external nuclear spins and resolve
their position within a few angstroms. The ability to bring the sensor close
to biomolecules by implantation of single NV centers and attachment ofproteins to the surface of diamond enabled the ﬁrst proof of principle

demonstration of proteins labeled by paramagnetic markers and label-freedetection of the signal from a single protein. Single-molecule nuclear

magnetic resonance (NMR) experiments open the way towards unravelingdynamics and structure of single biomolecules. However, for that purpose,
NV magnetometers must reach performance comparable to that ofconventional solution state NMR. We will discuss new techniques allowing
to combine high spectral resolution and sensitivity in nanoscale NMR. The
ability to sense nuclear spins by NV centers also enables the transfer ofpolarization from optically polarized spins of NV centers to external nuclear
spins. Such diamond based techniques for dynamic nuclear spinpolarization are very promising for the enhancement of sensitivity of
conventional MRI imaging.

087

SE-04-02

Programmable quantum simulators basedon spins in diamond
Tim Taminiau
QuTech and Kavli Institute of Nanoscience, Delft University of Technology, the Netherlands

Abstract
Spins associated to optically active defects in diamond provide a versatile

platform for quantum science and technology. In this talk, I will discuss ourrecent advances in realizing programmable quantum simulators based on

individually controllable carbon-�� nuclear spins in diamond. I will present

how one can use a single nitrogen-vacancy (NV) centre to sense, characterizeand control a large number of spins in its environment [�,�,�]. By controllingthe interactions between the spins it becomes possible to create a variety of
many-body Hamiltonians with tunable parameters. As an example, I will

discuss our investigation of a discrete-time crystal stabilized by many-body
localization, a new out-of-equilibrium phase of matter [�].
[�] M. H. Abobeih et al., Nature ���, ��� (����)[�] C. E. Bradley et al., Phys. Rev. X. �, ������ (����)[�] M. J. Degen et al., Nature Commun. ��, ����, ���� (����)[�] J. Randall et al., arXiv:����.����� (����)088

SE-04-03

Development and optimisation of diamondfor quantum technologies
Matthew Markham
Element Six

Abstract
Quantum technologies is attracting signiﬁcant investment due to the rangeof potential applications, but behind any new technology are the enablingmaterials. Diamond is one such material and ensembles ofnegatively-charged nitrogen-vacancy (NV-) centres constitutes a promising
platform for sensing applications utilizing the quantum properties of thisdefect. However, the sensitivity of present NV-ensemble devices and theneed for diamond material with reproducible properties has the potential tohinder progress toward many envisioned commercial-scale applications.
The work covered in this presentation will address the material-related

challenges associated with the development of diamond materials withreproducible properties for diamond quantum technologies.

089

SE-05-01

Quantum biology: an Introduction
Johnjoe McFadden
Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom

Abstract
Quantum mechanics and molecular biology were the two revolutionary
scientiﬁc disciplines that grew out of the twentieth century: quantum

mechanics and molecular biology. Quantum biology can be said to havebeen initiated by a physicist, Erwin Schrödinger, in his lecture, essay andbook entitled “What in Life” (published in ����) in which he proposed thatthat heredity was based on non-trivial aspects of quantum mechanics. The
book was very inﬂuential to molecular biology pioneers, such as James
Watson and Francis Crick, who went on to discover the double-helicalstructure of DNA. Thereafter the ﬁeld of quantum biology largely

languished. However, the twenty-ﬁrst century has seen a revival of quantum
biology with the arrival of new experimental evidence of quantum
mechanical eﬀects in a range of biological phenomena such as

photosynthesis and enzyme action. In this talk I will provide an introduction
to quantum biology, returning to Schrödinger’ s original insight thatquantum phenomena may be found in biological processes that involve

very numbers of molecules including photosynthesis, enzyme action, avian
navigation and mutation.

090

SE-05-02

Avian magnetoreception – a radical senseof directionPeter Hore
Department of Chemistry, University of Oxford, UK

Abstract
Small migratory songbirds travel spectacular distances each year,

navigating by a variety of means most of which are poorly understood.

Among them is a remarkable ability to perceive the direction of the Earth’ smagnetic ﬁeld. Despite more than �� years of research, the biophysicalmechanism of this extraordinary sense remains obscure. In this lecture, I
will discuss the proposal that the birds’ magnetic compass relies onlight-dependent chemical reactions in their eyes. Speciﬁcally, the uniquequantum mechanical properties of photochemically formed radical pairs incryptochrome proteins could allow detection of magnetic interactions sixorders of magnitude weaker than previously thought possible. I will outline
the basis of the radical pair mechanism, present some of the evidence forthe involvement of cryptochrome, and comment on the fundamentallyquantum nature of this hypothesis.

091

SE-05-03

Surface chemistry of diamond forquantum applications
Anke Krüger
Institute for Organic Chemistry, Stuttgart University, Germany

Abstract
The surface of diamond plays an important role for its properties. Not only is
the surface itself the origin of characteristics such as zetapotential

wettability, aggregation behaviour etc., also lattice defects such as the NV or
the SiV center can be inﬂuenced in their charge states by the nature of thesurface termination or the attachment of larger functional groups. The lattercan be also exploited for sensing applications using lattice defects asluminescent or spin sensors.

It is thus of utmost importance to properly control the surface groups and todevelop methods for the eﬃcient and highly reproducible functionalizationof diamond materials.

In this presentation, methods for the initial termination of diamond with

diﬀerent atoms such as H, O and F will be presented. Further, the attachmentof larger surface groups applicable as sensors, for the prevention of

non-speciﬁc interactions and other applications will be shown. Additionally,
highly sensitive methods for the quantitative assessment of surface groups
will be presented.

092

SE-05-04

Diamond-based quantum sensors: technology
and applications in physics and biology
Christian Degen
Department of Physics and Quantum Center, ETH Zurich, Switzerland

Abstract
Diamond has emerged as a unique material for a variety of applications,both because it is very robust and because it has defects with interesting

properties. One of these defects, the nitrogen-vacancy center (NV center),has a single spin associated with it that shows quantum behavior up to
room temperature. Our group is harnessing the properties of single NV
centers for high resolution magnetic sensing applications.

In this talk, I will introduce the basic technology and concepts and emerging
applications of diamond-based quantum sensors. I will discuss thechallenges in the fabrication of high-quality diamond probes, and present

some illustrative examples of applications in nanoscale imaging, including
the imaging of antiferromagnetic domains and domain walls, the ﬂow ofcurrent in graphene devices, and magnetic resonance imaging (MRI) of
nuclear spins with atomic spatial resolution.

093

SE-06-02

Classical and quantum sensing for precise
inertial navigation
Mikio Kozuma
Institute of Innovative Research, Tokyo Institute of Technology, Japan

Abstract
Inertial navigation is a technique to estimate self-position without the helpof external signals such as electromagnetic waves from GPS satellites. Sucha technique is essential, especially for controlling the position of theautonomous underwater vehicle since radio waves do not reach the deepsea. The current performance of the inertial navigation is the order ofkilometers for �� hours, which is not enough for various applications suchas marine resource exploration and data acquisition under Arctic sea ice. An
ultra-precise inertial navigation system can, in principle, be constructed byan accelerometer, gyroscope, and gravity gradiometer. Among them, thegyroscope and gravity gradiometer are key components to get highperformance. I will talk about our experimental eﬀorts to improve theprecision of inertial navigation using both classical and quantum sensors.

094

SE-06-03

Rotation sensing with the BIGTOP gyroscope
Cass Sackett
University of Virginia

Abstract
Precision rotation sensing is useful for navigation, geophysics, and tests offundamental physics. Atom interferometers provide, by some measures, themost sensitive method for rotation sensing achieved to date. However, thebest performance requires freely falling atoms in a large experimental

apparatus. Many applications, such as navigating a vehicle, will beneﬁt froma more compact geometry. One method to achieve this is by using trapped
atoms that are suspended against gravity. BIGTOP (Bragg Interferometer
Gyroscope in a Time-Orbiting Potential) implements such aninterferometer. It has been used to measure a rotation rates comparable tothat of the Earth, and recent improvements provide an enclosed area
approaching �� mm�.

095

SE-06-04

Development of transportable atomic
gravimeters for field applications
Ken'ichi Nakagawa
Institute for Laser Science, University of Electro-Communications, Japan

Abstract
Atomic interferometers are promising technology for precision

measurements of gravity and inertial forces. Atomic gravimeters based on
atomic interferometry are expected to be high-precision gravimeters for

geodesy, metrology, and geophysics. Transportable atomic gravimeters are
required in the ﬁeld applications such as seismology, gravity mapping. We

have developed a transportable atomic gravimeter for the ﬁeld applications.
Our atomic gravimeter is based on an atomic interferometer with cold ��Rb
atoms. We have developed a compact sensor head for the ��Rb atomic

interferometer using a small glass cell. The sensor head has a height of ��cmand a diameter of �� cm. We have also developed a compact laser system
based on ﬁber optics and frequency doubling of diode lasers at ���� nm.

Fast frequency switching of diode lasers enables to produce the lasers forcooling, Raman transition, and detection. In our preliminary experiment, we
could measure the interferometer fringe signal and determine the gravity
acceleration g with a precision of about dg/g = ��-�. By optimizing thesystem, the sensitivity is expected to be improved by more than two orders.
We will discuss the further investigation toward the realization of practicaltransportable atomic gravimeters for the ﬁeld applications.

096

SE-07-01

A Lu+ optical clock
Murray D Barrett
Center for Quantum Technologies, Singapore

Abstract
We give an overview of the Lu+ optical clock system developed in

Singapore. We outline the favorable properties and advantages this systemaﬀords as a high performance frequency standard. Supporting data

demonstrating high accuracy performance of a Lu+ frequency standard will
also be presented.

097

SE-07-02

Optical clocks based on multi-ion systems
Kazuhiro Hayasaka
Advanced ICT Research Institute, National Institute of Information
and Communications Technology, Japan

Abstract
The most successful implementations of the optical clock are single-ion

clocks and optical lattice clocks. In contrast to the large signal to noise ratiowith many atoms in the latter that of the former is limited by single ion.

However, in most of the ion clocks a single ion in a Paul trap has been used.
In this presentation we discuss our experimental studies to overcome

inhomogeneous frequency shifts of the ions, which hinder extension tomulti-ion systems. The one of the major shifts is the electric quadrupole

shift associated with the electric ﬁeld. In the ﬁrst strategy we use ion species
with null electric quadrupole moment. ���In+ ions in a linear trap realize
the extension to a multi-ion clock. The second strategy is to engineer thetrapping potential to suppress the quadrupole shift inhomogeneity.

We have found that ��Ca+ ions in the ʻiso-spacing potential’ implemented
with planar surface traps can be extended to the multi-ion clock. The last
strategy uses the macroscopic coherence of Ca+ ions prepared in the

iso-spacing potential. We found that coherent radiation by superradiancemight be observed when more than ���� Ca+ ions with the suppressed
quadrupole-shift inhomogeneity are coupled to an optical cavity.

098

SE-07-03

Strontium lattice clocks at PTB: transportable
and in the lab
Christian Lisdat
Physikalisch-Technische Bundesanstalt, Germany

Abstract
I will present our developments in the ﬁeld optical lattice clocks forapplications in the laboratory and as transportable devices. The talk willaddress a new laboratory clock with the capability of cryogenic

interrogation. I will present a new transportable interrogation laser systemwith below �E-�� fractional frequency instability and our plans for a newtransportable strontium lattice clock that targets �E-�� uncertainty.

Furthermore, I will discuss our progress concerning chip-based traps forstrontium.

099

SE-07-04

Lattice clock as a frequency standard
for JST and UTC
Tetsuya Ido
Space-Time Standards Laboratory, NICT, Japan

Abstract
The recent development of optical clocks inspires the expectation of a wide
variety of potential applications. But the results have been still in the realmof proof of principle experiments. However, in recent years, optical latticeclocks have ﬁnally achieved a social implementation. At NICT, the opticallattice clock is operated intermittently to build a timescale with its scaleinterval adjusted to the one second provided by an optical lattice clock.

The obtained data is also sent to the International Bureau of Weights andMeasures (BIPM), where BIPM adjusts the frequency of UTC with reference

to those data in addition to those from Cesium primary standards. I will talkabout the details of the optically-steered timescale and also discusspossible redeﬁnition of the SI second which may happen in ten years.

100Abstract

PL
TracksPlenary Sessions
Contents / Topics

Welcome from Organizing Committee and Hosting
Ministries, Plenary Talks, Keynote Speeches

CP
TracksQuantum Computing Track
Contents / Topics

Quantum Computing with Atoms and Ions,

Superconducting Quantum Computers(QC),
Photonic QC,Young Researcher

Session, Quantum Simulations, Semiconductor QC,

Quantum Annealing Toward FTQC(Tutorial), Beyond
NISQ/Toward

FTQC Panel Discussion,Quantum Architechture,

Quantum Algorithms, NISQ Algorithms,Quantum
Algorithms for ChemistryCC
TracksQuantum Cryptography &Communication Track
Contents / Topics

Quantum Internet, Quantum Cryptography(Up-to-date

Technologies of Field and Satellite QKDs), Challenges for
Quantum Technology

Platform (QKD Networks, Satellite QKD and theirintegration), Industry Panel, Young Researcher Session

SE
TracksQuantum Sensing Track
Short Presentations by
Young Researchers
SE-��A, ��B**CC-�� on �th and CC-��, CC-�� on �th Dec aresupported by SIP (cross-ministerial Strategic Innovation
promotion Program).

101

th
4 IFQMSThe 4th International Forumon Quantum Metrology and Sensing

PROCEEDINGS
Short Presentations by Young Researchers
Part 1: SE-03A

December 8th, 2021
Online Conference (Zoom)

Joint Program Session with Quantum Innovation 2021

102

Quantum Sensing Track : Short Presentations by Young Researchers
SE-03A. Short Presentations by Young Researchers on SE-01, 04, 06, 07 Topics [4th 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)
Dec 8 (Wed.)
13:10-14:30

Session / Presentation

Affiliation

ID

SE-03A-α1
MentorFedor Jelezko

MentorTakeshi Ohshima

QST

Mentor

Masaki Sekino

U TokyoUlm U

MentorTakayuki Iwasaki

Tokyo Tech

Chair

Motofumi Fushimi

U TokyoCo-chairChikara Shinei

NIMS

Exploring NV center formation condition for high Econv andcharge-state ratio of NV- and NV0 centers

Chikara Shinei

NIMS

SE-03A-α1-01

Sensitive atomic magnetometer beyond the standard quantum limit

Kosuke Shibata

Gakushuin U

SE-03A-α1-02

Uri Vool

Harvard U

SE-03A-α1-03

Xinyu CaoU TokyoSE-03A-α1-04

Hibiki Tabuchi

Keio U

SE-03A-α1-05

Peng Wang

Tokyo Tech

SE-03A-α1-06

Ryoma Matsuki

Tokyo Tech

SE-03A-α1-07

MentorSatoshi Yamasaki

Kanazawa U

MentorTokuyuki Teraji

NIMS

Imaging hydrodynamic flow in WTe_2 using cryogenic quantum
magnetometry
Toward on-board magnetoencephalography with wearable
magnetometers and active noise canceler
Continuous-wave temperature sensing using RF-dressed states ofnitrogen-vacancy centers in diamond
High-quality lead-vacancy centers in diamond by high-pressure andhigh-temperature annealing
Magnetocardiography imaging of living rats using NV centers inDiamond13:10-14:30

Mentor / Presenter

SE-03A-β1

MentorToshiharu Makino

AIST

MentorAkimichi Nakazono

YAZAKI

Chair

Hiroki Morishita

Kyoto U

Co-chairMoriyoshi Haruyama

AIST

Probing correlated phenomena in 2D materials with diamond quantum
Mark Ku
sensors
Electroluminescence observation of NV center in diamond lateral p-i-nMoriyoshi Haruyama
diode
Synthesis of HPHT diamond with controlled nitrogen concentration
Formation of diamond film containing perfectly aligned NV center
ensembles at a high growth rate by high-power density plasma CVD
High dynamic range current detection using a diamond quantum
sensorVector DC magnetic field sensing with the reference microwave fieldusing nitrogen vacancy centers in diamond
Thermal effects on generation of spin defects in hexagonal boron
nitrideU Delaware

SE-03A-β1-01

AIST

SE-03A-β1-02

Masashi Miyakawa

NIMS

SE-03A-β1-03

Takeyuki Tsuji

Tokyo Tech

SE-03A-β1-04

Yuta Shigenobu

Tokyo Tech

SE-03A-β1-05

Takuya Isogawa

Keio U

SE-03A-β1-06

Tetta Suzuki

Saitama U, QST

SE-03A-β1-07103Dec 8 (Wed.)
13:10-14:30

Session / Presentation

Affiliation

ID

SE-03A-γ1
Mentor

Keiichi Edamatsu

Tohoku U

MentorRyosuke Shimizu

UEC

MentorHirotaka Terai

NICT

MentorRyo Okamoto

Kyoto U

Chair

Fumihiro China

NICT

Co-chair

Le Bin Ho

Tohoku U

Error-disturbance uncertainty relations in faraday measurements

Le Bin Ho

Tohoku U

SE-03A-γ1-01

Hydrogen annealing effect on silicon optical waveguide

Yixin Wang

Tohoku U

SE-03A-γ1-02

Masaya Arahata

Kyoto U

SE-03A-γ1-03

Yuki Gama

Kyoto U

SE-03A-γ1-04

Phase retrieval of joint spectral amplitude

Kemeng Chen

UEC

SE-03A-γ1-05

Temporal shaping of an entangled-photon wave packet by fourier
optical synthesis

Hiroki Oshima

UEC

SE-03A-γ1-06

MentorTakuya Hirano

Gakushuin U

MentorTakashi Mukaiyama

Osaka U

Mentor

Masaki AndoU TokyoMentorTadashi Sakai

Tokyo Tech

Chair

Kiyotaka Aikawa

Tokyo Tech

Co-chairSatoru Takano

U Tokyo

Cryogenic monolithic interferometer for sensing gravity gradient

Satoru Takano

U TokyoSE-03A-δ1-01

Suspension noise measurements of cryogenic torsion pendulums with
Ching Pin Ooi
crystaline fibrfibres

U TokyoSE-03A-δ1-02

Angular sensor with a coupled cavity for gravity gradient sensing

Yuka Oshima

U TokyoSE-03A-δ1-03

Towards sensitive accelerometers with levitated single nanoparticles

Kiyotaka Aikawa

Tokyo Tech

SE-03A-δ1-04

Interferometric gyroscope using slow and continuous atomic beam

Tomoya Sato

Tokyo Tech

SE-03A-δ1-05

Osaka U

SE-03A-δ1-06

OIST

SE-03A-δ1-07

Wavelength-tunable broadband infrared quantum absorption
spectroscopy in the mid-infrared region 2-5 µm
Evaluation of superconducting nanowire single photon detectors for
mid-infrared wavelengths

13:10-14:30

Mentor / Presenter

SE-03A-δ1

Development of a quantum gyroscope based on a signle ion trapping
Ryoichi Saito
techniques
Exponentially enhanced quantum metrology by quenching superradiantKarol Gietka
light-matter systems beyond the critical point
14:50-16:10 SE-03A-α2
MentorFedor Jelezko

MentorTakeshi Ohshima

Ulm U
QST

Mentor

Masaki Sekino

U TokyoMentorTakayuki Iwasaki

Tokyo Tech

Chair

Chikara Shinei

NIMS

Co-chairMotofumi Fushimi

U TokyoThree-layered magnetically shielded room for ultrahigh-sensitivity
quantum sensing of biomagnetic signals

Motofumi Fushimi

U TokyoSE-03A-α2-01

Super-resolution in nanoscale NMR

Nicolas Staudenmaier

Ulm U

SE-03A-α2-02

Ryota Kitagawa

Tokyo Tech

SE-03A-α2-03

Hiroyoshi Tomioka

Tokyo Tech

SE-03A-α2-04

Shu Motoki

QST, Saitama U

SE-03A-α2-05

Ryusei Yanoshita

Kyoto U

SE-03A-α2-06

Sensitivity of weight imaging using a hybrid system based on
piezoactive magnetic material and diamond quantum sensor
Study on electron spin control method for high-sensitivity diamondquantum sensor
Optically detected magnetic resonance spectra of silicon vacancies in
4H-SiC with different temperatures
High efficiency formation of NV center inside diamond by femtosecond
laser

104

Dec 8 (Wed.)

Session / Presentation

Mentor / Presenter

Affiliation

ID

14:50-16:10 SE-03A-β2
MentorSatoshi Yamasaki

Kanazawa U

MentorTokuyuki Teraji

NIMS

MentorToshiharu Makino

AIST

MentorAkimichi Nakazono

YAZAKI

Chair

Moriyoshi Haruyama

AIST

Co-chair

Hiroki Morishita

Kyoto U

Hiroki Morishita

Kyoto U

SE-03A-β2-01

Hannes Kraus

NASA

SE-03A-β2-02

Kosuke Kimura

QST, Gunma U

SE-03A-β2-03

Kazuki Hirokawa

Tokyo Tech

SE-03A-β2-04

A compact quantum sensor head with side excitation of CVD diamond Yuki Nishio

Tokyo Tech

SE-03A-β2-05

Hybrid integration of Si3N4 grating structure on diamond NV substrate
Ryota Katsumi
for efficient photon extraction

Toyohashi Tech

SE-03A-β2-06

AC magnetic field sensing with ensemble NV centers using electricaldetection methods
OPuS-MAGNM - miniaturized optically pumped solid state quantum
magnetometers for space applications
Development of phthalocyanine ion beam for creation of multiple NV
centers.
Fabrication of diamond protective film using microwave plasma CVD
towards high-quality quantum emitters

14:50-16:10 SE-03A-γ2
Mentor

Keiichi Edamatsu

Tohoku U

MentorKenichi Nakagawa

UEC

MentorRyosuke Shimizu

UEC

MentorHirotaka Terai

NICT

Chair

Le Bin Ho

Tohoku U

Co-chair

Fumihiro China

NICTFumihiro China

NICT

SE-03A-γ2-01

Masayuki Hojo

Kyoto U

SE-03A-γ2-02

Hiroya Seki

UEC

SE-03A-γ2-03

Rui SunTohoku U

SE-03A-γ2-04

Yining Xuan

Tohoku U

SE-03A-γ2-05

Nicolas Schwaller

Kyoto U

SE-03A-γ2-06

Superconducting nanostrip single-photon detectors with dielectric
multilayer cavities
Estimation of the quantum efficiency of the up-conversion system
based on injection-locked dual oscillators
Selective measurement of biexciton luminescence by photon
correlation spectroscopy
Towards optical manipulation of gold-nanoparticles for efficient single
photon sources
Single photon emission from a quantum-dot-gold-nanostar coupledsystem on an optical nanofiber
Focusing constraints on coupling efficiency of collinear type-I
degenerated SPDC photon pairs into a single-mode fiber105

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α1-01
Exploring NV center formation condition for high Econv andcharge-state ratio of NV- and NV0 centers
Chikara Shinei1, Masashi Miyakawa1, Shuya Ishii2, Seiichi Saiki2, Shinobu Onoda2,
Kenji Watanabe1, Takashi Taniguchi1, Takeshi Ohshima2 and Tokuyuki Teraji1
1

National Institutes for Materials Science2

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

Introduction
Negatively-charged NV center (NV-) is promising color centers forhigh sensitivity magnetometer due to its long coherence time (~2 ms)
and clear Rabi and Ramsey contrast due to spin dependent
fluorescence 1. Weak DC magnetic signal detection such as detectionof single-neuron action potential 2, malarial hemozoin 3, biologicaltissue 4, and paleomagnetic in rocks 5, has been demonstrated using
ensemble of NV- center. For the weak DC magnetic signal detection,
diamond with [NT] ranged from 1 to 30 ppm and [NV-] ranged from0.1 – 4 ppm is empirically suitable. Assuming that the detectedvolume of diamond is constant, the magnetic sensitivity is
proportional to [NV-] which corresponds to the number of elementsof the magnetometer. Increasing of [NV-] is the most important for
improving the magnetic sensitivity. Generally, the conversion
FIG. 1. The relationship [NV-] / [NT] andefficiency (Econv) from substitutional nitrogen (Ns0) to NV- center,[NVT] /[NT]06[NV ] /[Ns ], must be increased in order to achieve higher [NV ] .
0
NV centers has also neutral charged state (NV ) which shows no spin dependent fluorescence. Since NV- and NV0
often coexist, fluorescence of NV0 becomes background and reduces fluorescence contrast of NV-. Thus, suppressionof NV0 formation while increasing Econv (or [NV-]) is important for improving the sensitivity.
Method and Result
Diamond single crystals used in this study were grown using either HPHT synthesis or CVD method. Substitutional
nitrogen concentration was controlled by tuning concentration of Ti in the metal solvent for the former while bychanging flow rate of nitrogen gas for the later. After the nitrogen doped diamond growth, an electron beam irradiation
was applied with the total fluence of 1017-1018 cm-2 to create vacancies in the diamond. it was followed by vacuum
annealing at 1000℃ for 2h to form NV center in the diamond crystals. The number density ratio of NV- to NV0 is
estimated from the intensity ratio of their ZPL. The [NV-] and [NT] was estimated using EPR method at room
temperature. [NVT] is equal to sum of [NV-] and [NV0].
In FIG. 1, the relationship between [NV-] / [NT] and [NVT] / [NT] measured by EPR and PL is presented. Circles
and squares respectively show synthesis method of HPHT and CVD. The color scale indicates substitutional nitrogenconcentration [NT] which was measured before electron beam irradiation process. The solid line shows the case inwhich [NV-] is equal to [NVT], indicating all NV center is negative charge state. The rate of increase of [NV-]/[NT]with respect to [NVT]/[NT] becomes smaller when [NVT]/[NT] is larger than 20 – 30%. The result indicate that the NV
centers were fully negatively charged when [NVT]/[NT] was up to about 20%. in our diamond samples. In thepresentation, we will discuss physical picture of charge state of NV center depending on [NVT] / [NT]: equilibrium
equation.
Reference
1

John F. Barry et al. Rev. Mod. Phys. 92, 015004 (2020).

2 J. F. Barry et al. Proc. Natl. Acad. Sci. U.S.A. 113, 14133 (2016).

I. Fescenko et al. Phys. Rev. Applied 11, 034029 (2019).
H. C. Davis et al. Nat. Commun. 9, 131 (2018).
5
D. R. Glenn et al. Geochem. Geophys. Geosyst. 18, 3254 (2017).
6
J. F. Barry et al. Rev. Mod. Phys. 92, 015004 (2020).
This work was supported by MEXT Q-LEAP (JPMXS0118068379 and JPMXS0118067395). T. Terajiacknowledges the support of, JST CREST (JPMJCR1773), MIC R&D for construction of a global quantum
cryptography network (JPMI00316), JSPS KAKENHI (Nos. 20H02187, 20H05661 and 19H02617). T. Teraji and
S. Onoda acknowledge the support of JST Moonshot R&D (JPMJMS2062).
3
4

106

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α1-02
Sensitive atomic magnetometer beyond the standard quantum limit
Kosuke Shibata, Naota Sekiguchi, Aki Torii, Junnosuke Takai, and Takuya Hirano
Department of Physics, Faculty of Science, Gakushuin University
shibata@qo.phys.gakushuin.ac.jp
Introduction
Atoms can be used for sensitive magnetometry. While vapor magnetometers have achieved sub fT Hz-1/2 sensitivities [1,2],
cold atom gases may work as sensitive and spatially-resolved magnetometers due to small thermal diffusion. Magnetic fieldsensitivities in the state-of-art atomic magnetometers are limited by the so-called standard quantum limit (SQL), which
results from quantum noises. Reduction of the quantum noises below the SQL has attracted attentions as a tool for enhancing
performance of a magnetometer.
We have constructed a sensitive magnetometer using a Bose-Einstein condensate (BEC) of rubidium atoms [3]. Our BEC
magnetometer sensitivity is already almost limited by quantum noises, consisting of the photon shot noise at detection andatomic spin shot noise. We aim to squeeze both of them to realize a sensitive magnetometer surpassing the classical ones.

MethodWe probe a BEC exhibiting the Larmor precession using a two-polarization phase contrast imaging. This imaging setup
detects difference in phase shifts of orthogonal circular components of an off-resonant probe at 795 nm, which is proportional
to the spin projection along the probe propagation axis and gives the information on the precession phase or a magnetic fieldat the atom position. The photon shot noise, which naturally appears in this difference detection, can be reduced by adding
a squeezed light to the probe. We have successfully generated a squeezed light at the probe wavelength using waveguides
and are now constructing a new squeezed light source near the BEC experiment machine. The two-polarization phase
contrast detection will introduce spin squeezing on the basis of quantum nondemolition (QND) measurement of an atomic
spin variable. We expect that planar squeezed state, which has quantum noise smaller than that in the coherent (classical)
spin state in the plane of the Larmor precession [4,5], should be generated in our experiment. The planar squeezed state will
improve the magnetic field sensitivity. We have conducted experiments to measure the atomic spin shot noise level and thespin squeezing. I will present on the details of these topics and our recent status.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118070326.

Reference

I.K. Kominis, T. W. Kornack, J. C. Allred, and M. V. Romalis, Nature (London), 422, 596-599 (2003).
S.-K. Lee, K. L. Sauer, S. J. Seltzer, O. Alem, and M. V. Romalis, Applied Phys. Lett., 89, 214106596-599 (2006).
3
N. Sekiguchi, K. Shibata, A. Torii, H. Toda, R. Kuramoto, D. Fukuda, and T. Hirano, Phys. Rev. A, 104, L041306 (2021).
4
Q. Y. He, Shi-Guo Peng, P. D. Drummond, and M. D. Reid, Phys. Rev. A, 84, 022107 (2011).
5
G. Puentes, G. Colangelo, R. J. Sewell, and M. W. Mitchell, New. J. Phys., 12, 053007 (2013).
1
2

107

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α1-03
Imaging hydrodynamic flow in 𝑾𝑾𝑾𝑾𝒆𝒆𝟐𝟐 using cryogenic quantum magnetometry
Uri Vool1, 2, Assaf Hamo2, Georgios Varnavides3, 4, 5, Yaxian Wang3, Tony X. Zhou2, 3, Nitesh
Kumar6, Yuliya Dovzhenko2, Ziwei Qiu2, 3, Christina A. C. Garcia3, Andrew T. Pierce2, Johannes
Gooth2, 6, 7, Polina Anikeeva4, 5, Claudia Felser3, 6, Prineha Narang3, and Amir Yacoby2, 3,

1John Harvard Distinguished Science Fellows Program, Harvard University
2

Department of Physics, Harvard University

3

John A. Paulson School of Engineering and Applied Sciences, Harvard University

4

Department of Materials Science and Engineering, Massachusetts Institute of Technology
5

Research Laboratory of Electronics, Massachusetts Institute of Technology
6

Max-Planck-Institut für Chemische Physik Fester Stoffe, Dresden

7Institut für Festkörper- und Materialphysik, Technische Universität Dresden

Hydrodynamic electron flow, where electrons in a conductor flow collectively - akin to a fluid, is a unique signatureof strong electron interactions in a material. This effect has been observed in 2D materials, but observations in bulk
materials are intriguing as high-carrier density should screen the interactions. In this talk, I will discuss a recent
measurement of hydrodynamic flow in the semimetal WTe2, allowing us to gain insight into the microscopic originof its electron interactions1.

We image the spatial profile of the electric current by using a nitrogen-vacancy scanning tip. Using coherent quantum
sensing, we obtain magnetic field resolution of ~10nT and spatial resolution of ~100nm. The current pattern we observe
differs substantially from the flat profile of a normal metal and indicates correlated flow through the semimetal. The
pattern also shows non-monotonic temperature dependence, with hydrodynamic effects peaking at ~20 K.
We compare our results to a model which combines ab initio electron scattering rates and the electronic Boltzmanntransport equation. The model shows quantitative agreement with our measurement, allowing us to extract the strengthof electron-electron interactions in our material. Furthermore, we conclude that electron interactions are phonon-me
diated. This result opens a path for hydrodynamic flow and strong interactions in a variety of new materials.

FIG. 1. Measurement technique: imaging local current flow by the effect of its induced magnetic field on a nitrogen-vacancy
sensor in a diamond tip.

Reference

U. Vool, A. Hamo, G. Varnavides, Y. Wang et. al. Nature Physics 17 1216-1220 (2021)

1

108

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α1-04
Toward on-board magnetoencephalography with wearable magnetometers andactive noise canceler
Xinyu Cao1, Zonghao Xin1, Akihiro Kuwahata2, Motofumi Fushimi1, Shinichi Chikaki1, Kazuhiro
Oyama3, Yuki Anno3, Teppei Yoshida3, Takayuki Shibata3, Yuichiro Shirota4, Masato Yumoto4,
Hiromasa Sawamura4, Mutsuko Hatano5, Takashi Yatsui6, and Masaki Sekino1
1

Graduate School of Engineering, The University of Tokyo
2

Graduate School of Engineering, Tohoku University
3

4
5

DENSO Corporation

Graduate School of Medicine, The University of Tokyo

Department of Electrical and Electronic Engineering, Tokyo Institute of Technology
6

Graduate School of Engineering, Toyohashi University of Technology
caoxinyu@g.ecc.u-tokyo.ac.jp

Introduction
Magnetoencephalography (MEG) is a non-contact biosignal measurement with high temporal and spatial resolution,
which has the potential to replace electroencephalogram (EEG) in various application scenarios. This study investigated thefeasibility of using wearable magnetometers for applications in on-board MEG. The results provide guidance information
for the development of MEG on-board measurement.
Methods
In this study, we proposed the potential application of wearable sensors in on-board MEG measurement, as shown in
Figure 1. The steady state visually evoked response (SSVER) signals were measured with superconducting quantum
interference devices (SQUIDs), and the signal distribution at potential on-scalp sensor positions were reconstructed withspherical head model [1] and minimum norm estimation (MNE) method [2]. The magnetic fields inside a real car were
measured. Noise reduction strategies based on active noise canceler for on-board applications were proposed.

FIG. 1. Schematic diagram of on-board MEG
measurement based on wearable sensors.

FIG. 2. The FFT of recorded magnetic field without/with
active cancellation. Note the change of the peak at 24 Hz.

Results and Discussion
The signal of the simulated wearable sensors is about 3 times that of the SQUID signal in this experiment. After the engine
was started, the AC magnetic field inside a gasoline car in an urban environment is about 7 times larger in the verticaldirection than in the horizontal direction. The piston movement of the internal combustion engine and the engine fan may be
two of the main causes of the magnetic field noise in the car. The highest signal-to-noise ratio of SSVER is -110 dB in thiscase. A 350 mm 20-turn active cancel coil can attenuate noise by about 28 dB at the target frequency, as shown in Figure 2.
Acknowledgements
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.
References
1
J. C. Mosher, R. M. Leahy and P. S. Lewis, IEEE. Trans. Biomed. Eng., 46, 245-259(1999).
2
S. Baillet, J. C. Mosher and R. M. Leahy, IEEE Signal Process Mag, 18, 14-30(2001).

109

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α1-05
Continuous-Wave Temperature Sensing
using RF-Dressed States of Nitrogen-Vacancy Centers in Diamond

Hibiki Tabuchi1,2, Yuichiro Matsuzaki3, Noboru Furuya1, Yuta Nakano4, Hideyuki Watanabe3,
Norio Tokuda4,5, Norikazu Mizuochi6, and Junko Ishi-Hayase1,2
1
2
34School of Fundamental and Technology, Keio University, Japan

Center for Spintronics Research Network, Keio University, Japan

National Institute of Advanced Industrial Science and Technology (AIST), Japan

Graduate School of Natural Science and Technology, Kanazawa University, Japan
5

Nanomaterials Research Institute, Kanazawa University, Japan
6

Institute for Chemical Research, Kyoto University, Japanhibiade0914@keio.jp
Introduction
Nowadays, there is a growing need to measure temperature with high sensitivity and special resolution to investigate theproperties of cells or nanodevices. A nitrogen-vacancy (NV) center in diamond is a promising candidate to realize a sensitive
temperature sensor with a high sensitivity and a special resolution. The temperature sensing using continuouswave_optically-detected magnetic resonance (CW-ODMR) has advantages because this can be simply implemented bycontinuous applications of a green laser and a microwave field. However, the temperature sensitivity with CW-ODMR istypically worse than that with pulsed-ODMR. Here, we propose a novel way to improve the sensitivity of temperature sensing
using CW-ODMR with a quantum state dressed by radio-frequency (RF) fields under the transverse magnetic fields.
MethodUnder applying the transverse magnetic fields with respect to the NV axis, the ground electronic spin states of NV centerare composed of |B⟩=(| + 1⟩+| − 1⟩)/√2, |D⟩=(| + 1⟩−| − 1⟩)/√2. The transition between |D⟩ and |B⟩ can be occurredby applying the resonant RF fields, which results in splitting into quantum states dressed by the RF fields as shown in Fig.1(a).
As the temperature increases, the resonant frequency of RF-dressed state shifts due to the change in the zero-field splitting 74.2 K/√Hz. Therefore, a temperature change can be estimated by measuring the temperature shift of RF-dressed state
observed in CW-ODMR spectra. The CW-ODMR spectra were measured by simultaneous application of continuous-waveof laser, MW, and RF fields as shown in Fig.1 (b).
Results and Discussion
Fig.1(c) shows the observed CW-ODMR spectra with the RF fields under the application of the transverse magnetic fields.
It is found the 4 peaks are clearly observed, which confirms the creation of RF-dressed states. The estimated sensitivity ofthe temperature sensing is calculated to be 73.0 mK/√Hz under the optimal conditions for the laser power, MW and RF
field intensities, and this value is 6 times better than that with the conventional scheme. This is because the linewidth becomesnarrower by suppressing the effect of the strain variations with increasing RF intensity. Moreover, the sharp dip structure
observed in the CW-ODMR contributes to improving the sensitivity.

FIG. 1. (a) The energy diagram of our system (b) Experimental setup to measure the CW-ODMR (c) Experimental Result
This work was supported by MEXT Q-LEAP (No. JPMXS0118067395), MEXT KAKENHI (No. 18H01502), and CSRN,
Keio University. This work was also supported by Leading Initiative for Excellent Young Researchers MEXT Japan andJST presto (Grant No. JPMJPR1919) Japan.
Reference
T. Yamaguchi, et al., Jpn. J. Appl. Phys., 58, 100901 (2019).2Y. Matsuzaki, et al., J. Phys. Condens. Matt., 28, 275302 (2016).
K. Hayashi, et al., Phys. Rev. Appl., 10, 034009 (2018). 4S. Saijo, et al., Appl. Phys. Lett., 113, 082405 (2018).

1
3

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Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α1-06
High-quality lead-vacancy centers in diamondby high-pressure and high-temperature annealing
Peng Wang1, Takashi Taniguchi2, Yoshiyuki Miyamoto3, Mutsuko Hatano1 and Takayuki Iwasaki1
1

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
23International Center for Materials Nanoarchitectonics, NIMS, Japan

Research Center for Computational Design of Advanced Functional Materials, AIST, Japanwang.p.ac@m.titech.ac.jp

Introduction
Color centers in diamond have aroused great interests nowadays: especially heavy group-IV vacancy centers in diamond are expected
to possess sharp Zero phonon lines (ZPLs) and predicted long spin coherence times1, serving as promising candidates for quantum
network. However, the heavy atom (such as lead atom) suffers from difficulty in introducing into the diamond lattice during ion
implantation, resulting in strong strained environment around lead vacancy (PbV) center. Such strained environment resulted in broad
florescent emission, making it difficult to investigate properties of the PbV center. In order to observe its energetic structure and move
forward to wavelength tuning or spin measurement, there is an urgent demand for high quality PbV whose fine structure could beclearly demonstrated, which requires an efficient approach to release the strain and recover defects formed during ion implantation.

Method and Results

For the fabrication of high-quality PbV centers in diamond, we adopted high-pressure and high-temperature (HPHT) annealing after
Pb ion implantation, at 2100℃ under 7.7 GPa. Such a high temperature is considered to reduce the strain and recover defects indiamond, while the high-pressure condition maintains the stable phase of diamond. The same procedure has been proved to reduce
inhomogeneous distribution of tin-vacancy center in diamond1,2.
We show a sharp and clear spectrum of single PbV at around 6 K, in which the linewidth of C-transition was limited to thespectrometer3. By recording Hanbury Brown-Twiss (HBT) measurement at varying excitation powers, the single configuration was
confirmed by antibunching, and we were able to estimate the excited state lifetime according to time correlation4, ~3.7 ns, as shown in
Fig. 1. Besides, our major concern is the strained environment around PbVs, which can be evaluated by their spectral distribution. We
depicted the inhomogeneous distribution of the C-transition, which turned out a linewidth of 155 GHz, as shown in Fig. 2. Comparedwith former reported distribution of 10 nm with 950℃ annealing5, our experimental results indicated that the inhomogeneous energetic
distribution of PbVs were suppressed by HPHT annealing. Such narrow distribution is of vital importance for further research on photon
indistinguishability.
This work was supported by Toray Science Foundation and MEXT Q-LEAP Grant Number JPMXS0118067395.

Fig. 2 Inhomogeneous distribution of PbVs
Fig.1 Estimated excited state lifetime of a single PbV

Reference
1.
2.
3.
4.
5.

Iwasaki, T. et al. Tin-Vacancy Quantum Emitters in Diamond. Phys. Rev. Lett. 119, 253601 (2017).
Goerltz, J. et al. Spectroscopic investigations of negatively charged tin-vacancy centres in diamond. New J. Phys. 22,013048 (2020).
Wang, P., Taniguchi, T., Miyamoto, Y., Hatano, M. & Iwasaki, T. Low-Temperature Spectroscopic Investigation of LeadVacancy Centers in Diamond Fabricated by High-Pressure and High-Temperature Treatment. ACS Photonics 8, 2947–
2954 (2021).
Khalid, A. et al. Lifetime Reduction and Enhanced Emission of Single Photon Color Centers in Nanodiamond via
Surrounding Refractive Index Modification. Sci. Rep. 5, 11179 (2015).
Fröch, J. E. et al. Versatile direct-writing of dopants in a solid state host through recoil implantation. Nat. Commun. 11,5039 (2020).
111

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α1-07
Magnetocardiography imaging of living rats using NV centers in Diamond
Ryoma Matsuki1, Keigo Arai1,2, Akihiro Kuwahata3, Daisuke Nishitani1, Ikuya Fujisaki1, Yuki Nishio1,
Zonghao Xin3, Xinyu Cao3, Yuji Hatano1, Shinobu Onoda4, Chikara Shinei6, Masashi Miyakawa6, Takashi
Taniguchi6, Masatoshi Yamazaki7,8, Tokuyuki Teraji5, Takeshi Ohshima4, Mutsuko Hatano1,4, Masaki
Sekino3, and Takayuki Iwasaki 1
1Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2Japan Science and Technology PRESTO, Saitama, 332-0012, Japan
3Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656, Japan
4National Institutes for Quantum and Radiological Science and Technology, Takasaki, 370-1292,Japan
5Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, 305-0044, Japan
6International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, 305-0044, Japan

Department of Cardiology, Nagano Hospital, Soja, 719-1126, Japan
Medical Device Development and Regulation Research Center, The University of Tokyo, Tokyo, 113-8656, Japanmatsuki.r.aa@m.titech.ac.jp
78

Introduction
Diamond quantum sensors based on nitrogen-vacancy (NV) centers have high spatial resolution operated at room
temperature even under large background magnetic fields. We constructed a sensor system suitable for bio-magnetic
measurement that can take advantage of the ability to bring the NV center closer to the signal source under ambient operating
conditions. In this study, we introduce magnetocardiography(MCG) signal, mm-scale MCG imaging, and reconstruction ofcurrent in living rats.[1].

Experimental procedures and Results

We constructed a compact sample holder that allows the distance between a live rat heart and a diamond sample to be as
close as about 1 mm as shown Fig.1(a), and measured MCG of living rats. Moreover, we conducted MCG imaging at
11x11=121 measurement points over 30 mm by automatically moving the XY stage with rats on it, and reconstructed thecurrent density using bfieldtools[2,3] an open-source Python software suite. As a result, we measured MCG in a living rat atseveral tens of nT as shown Fig. 1(b), and reconstructed the current density distribution from MCG imaging with mm-scalespatial resolution as shown Fig. 1(c)(d). In addition, we conducted experiments with multiple rats using this sensor system,
and confirmed that similar results could be obtained.
Acknowledgments
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.

Reference[1] K.Arai et al., arxiv:2105.11676(2021).
[2] Mäkinen, A. J. et al., J. Appl. Phys.128, 063906 (2020)[3] Zetter, R. et al., J. Appl. Phys.128, 063905 (2020)

c

d

Fig.1

(a) Schematic of the rat MCG setup.

(b) MCG signal from a rat.

(c) (d) MCG imaging and reconstructed current distribution combined with MRI.

112

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β1-01
Probing correlated phenomena in 2D materials with diamond quantum sensors
Mark J.H. Ku1
1

Department of Physics and Astronomy and Department of Materials Science and Engineering, University of
Delawaremku@udel.edu

Understanding correlated spin and charge phenomena presents a rich arena for discovering exotic behaviors in materials
and plays a critical role in developing next-generation information processing capabilities. 2D systems realized with van der
Waals materials provide particularly interesting platforms for exploring correlated phenomena because of novel effects
associated with reduced dimensionality and the opportunity for drastic miniaturization and for creating new functionality.
Hence, understanding correlated phenomena in 2D materials is a frontier in condensed matter physics; however, this effort
encounters numerous challenges related to measurement techniques, including spatially-varying current or spin distribution,
small device dimension, and complex device geometry (e.g. heterostructure. Due to the ability to image magnetic field fromcurrent and spins with high spatial resolution over wide temperature range, quantum sensing with nitrogen-vacancy (NVcenters in diamond provides a transformative tool for studying condensed matter phenomena. In this talk, I will discuss two
topics in 2D materials probed with NV quantum sensing. We have directly imaged viscous flow of the Dirac electron fluidin graphene via NV magnetic imaging [1]. Understanding of the Dirac fluid presented in this work provides insight into
strongly-correlated electrons such as those in high-temperature superconductors. Via NV magnetic imaging, we have also
directly established room-temperature ferromagnetism in exfoliated flakes of Fe5GeTe2 (FGT [2] for the first time as wellas in Co-doped FGT (Co-FGT. As a step towards detecting magnons (spin excitations in 2D magnets, we have also obtained
the first ferromagnetic resonance measurement of Co-FGT bulk crystal. These results contribute towards the applications of
2D magnets in technologies and devices.

References[1] M.J.H. Ku, T.X. Zhou, Q. Li, Y.J. Shin, J.K. Shi, C. Burch, L.E. Anderson, A.T. Pierce, Y. Xie, A. Hamo, U. Vool,[2]

H. Zhang, F. Casola, T. Taniguchi, K. Watanabe, M.M. Fogler, P. Kim, A. Yacoby, and R.L. Walsworth,Nature 583, 537 (2020).

Hang Chen, Shahidul Asif, Matthew Whalen, Jeyson Tamara-Isaza, Brennan Luetke, Yang Wang, Xinhao
Wang, Millicent Ayako, Andrew F. May, Michael A. McGuire, Chitraleema Chakraborty, John Q. Xiao, andMark J.H. Ku, arXiv:2110.05314 (2021).

113

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β1-02
Electroluminescence Observation of NV Center in Diamond Lateral p-i-n Diode
Moriyoshi Haruyama1, Hiromitsu Kato1, Masahiko Ogura1, Yukako Kato1, Takayuki Iwasaki2,
Norikazu Mizuochi3, and Toshiharu Makino1
1
2

National Institute of Advanced Industrial Science and Technology

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
3

Institute for Chemical Research, Kyoto University
haruyama.moriyoshi@aist.go.jp

Introduction
Nitrogen Vacancy (NV) center in diamond is one of the most studied color centers. Especially in negatively charged NV
center (NV- center), electron spin state initialization and readout can be easily performed by laser irradiation. On the other
hand, electrical manipulation of NV center without laser is required for chip-scale quantum device development. In 2013,
two papers were reported about electroluminescence of NV center, however electrical excitation of NV- center was notrealized. It can be expected that charge state of NV- center was stabilized by increasing electron concentration around NV
center. To realize this, we fabricate high concentration phosphorus doped n layer. In this study, we tried observation ofelectroluminescence from NV center in the lateral p-i-n diode and investigate the electroluminescence characteristics.

MethodResults
0

0

2 μm
(c)

2 μm
(d)
Intensity(a.u.)

Intensity(a.u.)

Figure 1 (a) and (b) shows PL and EL CFM
map in i layer. The EL measurement was
performed under applied 30V of forward
bias. As shown in these figure, isolated
luminescent centers were observed at same
position. Figure 1 (c) and (d) show PL and EL
spectra of luminescence center. Zero phononline of NV- center was detected from PL
spectrum, while zero phonon line of NV0
center was detected from EL spectrum. In
theseresults,
wesucceedinelectroluminescence observation of NV
center by using lateral p-i-n diode. In
presentation, we will report analysis result
about NV– component in the EL spectrum.

Photon count (kcps)

Photon count (kcps)

We fabricated p-i-n diode by using microwave plasma enhanced chemical vaper deposition (CVD) method. The i layer
was grown on the (111) Ib high pressure high temperature diamond substrate. The i layer was slightly doped phosphorus tostabilize charge state of NV- center (P concentration: 1016 cm-3). Patterned boron doped p+ and phosphorus doped n+ layer
were grown on the i layer. Both of boron and phosphorus concentration in p+ and n+ layer was 1020 cm-3. After CVD growth,
we performed nitrogen ion implantation and post-annealing to create NV center. Acceleration energy, ion fluence andimplantation temperature were 350 keV
ELPL
5×108 cm-3 and 600oC, respectively. Post200
100
(a)
(b)
annealing temperature and time were 850oC,
30 min, respectively. After post-annealing,boiled acid mixture treatment (H2SO4 andHNO3) was performed to terminate surface
with oxygen. Electrode (Ti / Pt / Au) was
created on both p+ layer and n+ layer.

Wavelength(nm)Wavelength(nm)FIG. 1. (a) PL CFM map. (b) EL CFM map. (c) PL spectrum. (d) EL
spectrum.

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

Reference
1

N. Mizuochi et al., Nature Photonics, 6, 299 (2012)
A. Lohrmann et al., Applied Physics Letter, 99, 251106 (2011)

2114

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-3A-β1-03
Synthesis of HPHT diamond with controlled nitrogen concentration
Masashi Miyakawa1, Chikara Shinei1, Takashi Taniguchi2, and Tokuyuki Teraji1
1
2

Research Center for Functional Materials, National Institute for Materials Science

International Center for Materials Nanoarchitectonics, National Institute for Materials Science
MIYAKAWA.Masashi@nims.go.jp

Introduction
For developing quantum sensing devices, it is essential to utilize diamonds containing NV center with desiredconcentration. The desired concentration of NV centers varies from 1 ppb to 10 ppm, depending on applications in quantum
sensing devices. Thus, control of NV center concentration with a wide range is requested in diamond growth method. In caseof diamonds grown under high-pressure and high-temperature (HPHT), NV centers are usually formed by electron beamirradiation to nitrogen-doped diamonds followed by post-annealing treatments. Here, precise control of the substitutional
nitrogen (P1) center concentration during HPHT growth process with a wide range is a key for the concentration control of
NV center. There were reports that nitrogen impurity was reduced to the limit by adding a nitrogen getter of Ti or Al,1-4 but
continuous control of nitrogen concentrations in wide range of the order of 100 to 0.1 ppm was not. In this paper, we willreport the controllability of the nitrogen in the HPHT diamond synthesized with Co-Ti and Fe-Co-Ti base solvents by using
Ti as a nitrogen getter.

MethodSingle-crystalline diamonds were grown in Co-Ti and Fe-Co-Ti solvents by a temperature-gradient method using amodified belt-type high-pressure apparatus. Graphite and diamond with different boron impurity levels were used as carbon
sources. Pressure, temperature, and growth duration were 5.5 GPa and 1350oC for 40~80 h. Concentration of the P1 center
was evaluated by electron spin resonance (ESR) measurements using a piece of diamond with (111) faces obtained by cutting
parallel to (111) plane.

Results and discussion

ESR measurements indicated P1 center concentrations were exponentially decreased from 100 ppm to 0.1 ppm withincreasing amount of Ti additives in the Co-Ti solvent, which provides the nitrogen concentration in diamond crystals canbe controlled by optimizing amount of Ti additive. In the Fe-Co-Ti solvents, P1 concentration was decreased from ~90 ppm
to ~0.08 ppm with increasing amount of Ti additive up to 2 wt%, and efficiency of nitrogen gettering by Ti additives washigher compared with the Co-Ti solvents. Moreover, it was found that selection of carbon source became important when
the P1 concentration < ~0.2 ppm. The result of SIMS measurements indicated that residual boron concentrations in the growndiamonds were ~0.2 ppm when graphite was used as a carbon source and ~0.02 ppm when CVD diamond was used. Residualboron compensates for the P1 center, leading to an unexpected lower concentration of the P1 centers in the grown diamonds.
Therefore, utilizing a high-purity carbon source such as CVD diamonds was found to be efficient for suppressing
contamination by boron impurities in the synthesized diamonds with the P1 concentration < ~0.2 ppm.

Reference

H. Sumiya, S. Satoh, Diam. Relat. Mater., 5, 1359 (1996).
R.C. Burns, J.O. Hansen, R.A. Spits, M. Sibanda, C.M. Welbourn, D.L. Welch, Diam. Relat. Mater., 8, 1433 (1999).
3
H. Kanda, Braz. J. Phys., 30, 482 (2000).
4
A. D’Haenens-Johansson, K.S. Katrusha, P.J. Moe, W. Wang, Gems Gemol., 51, 260 (2015).
1
2

Acknowledgements
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118068379.

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SE-03A-β1-04
Formation of diamond film containing perfectly aligned NV center ensembles at
a high growth rate by high-power density plasma CVD

Takeyuki Tsuji1, Hitoshi Ishiwata1,2, Takeharu Sekiguchi1, Takayuki Iwasaki1, and Mutsuko Hatano1
1

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2

PRESTO, Japan Science and Technology Agency
tsuji.t.ac@m.titech.ac.jp

Diamond film sensors with large volumes (> (0.5 mm)3) containing perfectly aligned nitrogenvacancy (NV) ensembles performing high contrast (≈ 30%) are a promising material forachieving highly sensitive quantum magnetometers such as magnetoencephalography. The stepflow growth mode in which diamonds grow laterally by microwave plasma chemical vapor
deposition (MPCVD) is required to realize aligned NV center ensembles. However, theconventional growth rate of aligned NV center ensembles was limited to a low value (0.05~ 0.5μm/h) because a low gas flow ratio CH4 / H2 (< 0.5%) is needed for step flow growth [1–3]. In
addition, the nitrogen density of the NV center film should be controlled to below 30 ppm toobtain high contrast because the high nitrogen densities shorten the life-time of the excited-state
and reduce spin polarization, which leads to decreased the contrast [4].
In this study, we achieved a high growth rate (6.6 µm/h) of diamond film containing perfectlyaligned NV ensembles with high contrast (30%) by applying high power density plasma (103
W/cm3) and precisely controlling the flow rate ratios of CH4 / H2 and N2 / CH4. For introducing
high power density plasma, we used an MPCVD with a spherical chamber to reflectively
concentrate microwaves on the diamond stage with a microwave antenna, and higher gas
pressure up to 30 kPa was introduced to concentrate the plasma on the diamond substrate. The
power density was varied as 42, 66, 103 W / cm3, which belongs to the high-density regime (>40 W/cm3) among the previous diamond CVD studies [5]. The growth temperature of 800 °C
and growth time of 4 hours are fixed during the CVD growth.
The three-dimensional island growth was observed at the CH4 / H2 of 0.32% because of thenucleation formed on the terraces. Then, the hydrogen etching of the nucleation formed on theterraces was induced by decreasing the CH4 / H2 to below 0.16% leading to step-flow growth.
Fig.1 shows that the growth rate of the diamond films with step flow growth were increased
as the power density was increased. It was considered that increasing the power density, which
can produce a large amount of carbon precursors while maintaining a low CH4 / H2 of 0.16%,
realized step-flow growth, leading to a high growth rate (6.6 µm/h) with perfectly aligned NV
center ensembles. The N2 / CH4 ratio was also controlled to be lower than 2.5%, and thenitrogen density in the diamond film was kept below 30 ppm to obtain a high Rabi contrast(30%) as shown in Fig2. Moreover, we measured the T2* of the obtained diamond sensor films
by the high growth rate with the Ramsey sequence using a large detection volume of
approximately 8000µm3. We confirmed that T2* (= 210 ns) obtained in this study is mainly
limited by nitrogen electron spin bath density of the diamond film (24 ppm) [6] and no
significant decrease in T2* due to the deterioration of the crystallinity of the diamond film
including strain gradients was observed. This result is promising for building material
technology for highly sensitive quantum sensors with large sensor volumes.

Acknowledgment

This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395. andconducted at (NanofabPF, Tokyo Tech), supported by "Nanotechnology Platform Program" ofthe Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, Grant
Number JPMXP09F-21-IT-014.

Fig.1. (a) Evolution of thegrowth rate of the CVD
diamond films with island
growth (triangular red dots) or
the step-flow growth (circle
black dots) as a function of the
MW power density.

Fig.2. The nitrogen density in
the CVD film (circle blue dots)
and Rabi contrast (triangular
red dots) dependence on N2 /CH4. To obtain high contrast (≈30%), N2 / CH4 was controlled
to be lower than 2.5%.

Reference[1] H. Ozawa, K. Tahara, H. Ishiwata, M. Hatano, and T. Iwasaki, Appl. Phys. Express 10, 045501 (2017).
[2] H. Ishiwata, M. Nakajima, K. Tahara, H. Ozawa, T. Iwasaki, and M. Hatano, Appl. Phys. Lett. 111, 043103 (2017).
[3] P. Balasubramanian, C. Osterkamp, Y. Chen, X. Chen, T. Teraji, E. Wu, B. Naydenov, and F. Jelezko, Nano Lett. 19,6681 (2019).
[4] K. Mizuno, M. Nakajima, H. Ishiwata, M. Hatano, and T. Iwasaki, Appl. Phys. Express 14, 032001 (2021).
[5] T. Teraji, T. Yamamoto, K. Watanabe, Y. Koide, J. Isoya, S. Onoda, T. Ohshima, L. J. Rogers, F. Jelezko, P. Neumann,
J. Wrachtrup, and S. Koizumi, Phys. Status Solidi 212, 2365 (2015).
[6] E. Bauch, S. Singh, J. Lee, C. A. Hart, J. M. Schloss, M. J. Turner, J. F. Barry, L. M. Pham, N. Bar-Gill, S. F. Yelin,and R. L. Walsworth, Phys. Rev. B Condens. Matter 102, 134210 (2020).

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SE-03A-β1-05
High dynamic range current detection using a diamond quantum sensor
Yuta Shigenobu1, Yuji Hatano1, Jaewon Shin2, Junya Tanigawa2, Akimichi Nakazono2,

Shinobu Onoda3, Takeshi Oshima3, Keigo Arai1, Mutsuko Hatano1, 3, Takayuki Iwasaki1
1

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
Yazaki Corporation,

2

3

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

Introduction
High dynamic range current detection is required to estimate the remaining charge in the battery and precisely predict
the travelable mileage of EV. The maximum current flowing bus-bars connecting the battery will reach to several hundred
amperes. Simultaneously, the measurement with 10 mA accuracy in the well-controlled temperature is required to expand
the travelable mileage up to 10 %1. Thus, 5-digit dynamic range current sensor is crucial to realize an efficient battery
system. In this study, to meet these requirements, we constructed a quantum sensor system using ensemble NV centers indiamond.

MethodExperimental set-up to measure the bus-bar current with the diamond sensor is shown in FIG.1. The diamond sensor
used was a (111) type-Ib HPHT crystal, with a size of 2.0 ✕ 2.0 ✕ 1.0 mm3 and 3.0 ✕ 1018 cm-2 EB irradiation. The
sensor was attached to one end of a multi-mode fiber to excite by green laser and to collect the red fluorescence from theNV centers. The diamond sensor was placed perpendicular to the bus-bar to coincide the current magnetic field direction
with the N-V axis. Since the magnetic field strength in the diamond sensor generated by the 1000 A bus-bar current wasestimated to be 9 mT, 15 mT static magnetic field was applied by Nd magnets. The magnetic field was measured as thedifference in the lock-in-amplifier (LIA) outputs in the two resonance frequencies generated by the microwave signal
generator (SG)2.

ResultThe obtained spectrum of the magnetic field noise measured when SG and LIA were modulated by the frequency of
Fmod = 20 kHz and the depth of Fdev = 3.5 MHz is shown in FIG.2. The noise floor of the sensor system was less than 10
nT⁄√Hz. This value is enough to measure the magnetic field generated by the 10 mA around the bus-bar. The current
measurement procedure was as follows. The feedback path from LIA through integrator circuit to SG in FIG.1 is always
stable if the magnetic field variation caused by the bus-bar current is within a few MHz, which we define as D, where theslope of CW-ODMR around the resonance frequency is monotonous. For the small range, a current pulse train withchanging amplitude from 100 mA to 10 mA was applied and the 10 mA pulse could be detected as the change of theintegrator output. Even if the current change was over D, the feedback was kept stable by repeating the intermittent
adjustment of the center frequency of SG when the integrator circuit output reaches a predetermined value below D (forexample, 𝐷𝐷 ⁄2). The current was incremented or decremented with 30 A amplitude and 2 s width steps. We confirmed thatthe feedback path could track the current variation up to ±1000A provided.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.

Reference

H. Sugiyama et al., OP2, IFQMS3 (2020)

2

Y. Hatano et al., Appl. Phys. Lett. 118, 034001 (2021)
Magnetic field fluctuation (nT/Hz1/2)

1

FIG.1 Experimental setup for measuring the bus-bar
current with diamond sensor (left) and its expansion
around the diamond sensor (right).

1000
100
10
1
0.1
0.01
0.1

1

100
10
Frequency (Hz)

1000

10000

FIG.2 Measured noise spectrum of the
diamond sensor at 15 mT magnetic field and100 mW laser power.

117

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β1-06
Vector DC magnetic-field sensing with reference microwave fieldusing a single nitrogen-vacancy center in diamond
Takuya Isogawa1,*, Yuichiro Matsuzaki2,†, and Junko Ishi-Hayase1,‡
Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan

1

National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan2

tisogawa@keio.jp †matsuzaki.yuichiro@aist.go.jp ‡hayase@appi.keio.ac.jp*

Introduction
The measurement of DC magnetic fields at the nanoscale is important in various fields such as condensed matter physics[1]. In particular, a single nitrogen vacancy (NV) center in diamond is a promising device to achieve high sensitivity andspatial resolution. Recent studies have shown that vector DC magnetic-field sensing using a single NV center provides higher
readout contrast and spatial resolution compared to conventional methods using NV center ensembles [2, 3]. However, thesemethods require the application of a reference DC field that may disturb the target system in order to estimate the azimuthal
angle of the target magnetic field with respect to the NV axis. This can be a severe problem for materials that are sensitive
to static magnetic fields. Here, we propose a scheme to measure vector DC fields without a reference DC field. The azimuthal
angle of the target magnetic field can be measured from the Rabi frequency, using the direction of the microwave field todrive the Rabi oscillation as a reference. The proposed scheme delivers a novel technique for sensitive vector DC magneticfield sensing with a single NV center.

Measurement of the azimuthal angle of the target DC magnetic field

The components perpendicular and parallel to the NV axis of the target magnetic field are estimated from the two
resonance frequencies. While the azimuthal angle can be determined by applying a reference DC field to the system (Fig.
1a), our method provides a way to determine the azimuthal angle of the target field using the direction of the microwave asa reference (Fig. 1b). The perpendicular component of the target magnetic field tilts the quantization axis from the NV axis.
When a linearly polarized resonant microwave is applied, Rabi oscillation occurs at the frequency proportional to thecomponent of the microwave perpendicular to the quantization axis. Therefore, the tilt of the quantization axis can be
determined from the Rabi frequency, and the direction of the applied DC magnetic field can be measured. Fig. 1c shows thesensitivity of the conventional scheme and our scheme. The simulation was performed by solving the master equation in thepresence of Markovian dephasing. Here, we have used the same decay rate in the calculation of the sensitivity of bothschemes. In the actual experiments, we expect that our scheme can achieve higher sensitivity because the coherence time of
the Rabi oscillation is usually longer than that of the Ramsey interferometry.

FIG. 1. (a) Configuration of NV axis, the target DC magnetic field, and the reference DC magnetic field. (b) Configurationof NV axis and the reference microwave field. (c) Sensitivity of the conventional scheme (blue) and our scheme (red) as afunction of the azimuthal angle 𝜙𝜙 for 𝜃𝜃 = 10° (solid), 𝜃𝜃 = 40° (dashed), and 𝜃𝜃 = 80° (dotted). Here we fix 𝐵𝐵 =8 mT, 𝐵𝐵mw = 1 mT, 𝐵𝐵𝑟𝑟 = 1 mT, and 𝜃𝜃mw = 20°. The decay rate is 1.0 × 106 .

Acknowledgements

This work was supported by MEXT Q-LEAP (No. JPMXS0118067395), MEXT KAKENHI (No. 18H01502), and CSRN,
Keio University. This work was also supported by Leading Initiative for Excellent Young Researchers MEXT Japan andJST presto (Grant No. JPMJPR1919) Japan.

Reference

F. Casola, T. Van Der Sar, and A. Yacoby, Nature Reviews Materials 3, 1 (2018).
X.-D. Chen, F.-W. Sun, C.-L. Zou, J.-M. Cui, L.-M. Zhou, and G.-C. Guo, Europhysics letters 101, 67003 (2013).
3
Y.-X. Liu, A. Ajoy, P. Cappellaro, Physical Review Letters 122, 100501 (2019).
1
2

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SE-03A-β1-07
Thermal effects on generation of spin defects in hexagonal boron nitride
Tetta suzuki1,2, Yuichi Yamazaki2, Takashi Taniguchi3, Kenji Watanabe3,
Yu-Ichiro Matsushita4, Yuta Masuyama2, Yasuto Hijikata1, Takeshi Ohshima2
1

Saitama Univ, 2QST, 3NIMS, 4Tokyo Techt.suzuki.838@ms.saitama-u.ac.jp

Introduction
There has been a lot of research on quantum sensors based on spin defects in wide gap semiconductors such as nitrogenvacancy complex defect (known as NV center) in diamond, silicon vacancy in silicon carbide. Recently, hexagonal boron
nitride (hBN), a 2D material, has been attracting attention as a new mother material for spin defect1,2. Energetic particle(electron, ion and neutron) irradiation is the most typical method to generate spin defects. However, such a method also
introduce unnecessary defects degrading spin property of spin defect. Thermal treatment is a useful method to anneal residual
defects. The effect after irradiation as well as during irradiation (high temperature irradiation) has been studied 3,4. In thispaper, we investigated the thermal effect on generation of boron vacancy defect (VB) in hBN.
MethodWe used hBN flakes on SiO2/Si substrate formed by tape transfer method which is commonly used in graphene research.
40 keV-N2 ions were irradiated with the optimized fluence of 1×1015 cm-2 at room temperature. Then, the irradiated sample
was isochronally annealed up to 800 °C. For comparison, 40 keV-N2 ion irradiation at elevated temperature up to 800 °C
was carried out. The photoluminescence (PL) spectra were measured using a HORIBA LabRAM HR Evolition (laser
wavelength: 532 nm, laser power: 0.1 mW). Optically detected magnetic resonance (ODMR) measurements were performed
using a home-made confocal microscope. We used a software-based the lock-in detection for the ODMR measurements.
ResultPL intensity and ODMR signal contrast as a function of treatment temperature were shown in Fig. 1 and 2. In the postannealing experiment, the PL intensity remained almost the same up to 400 °C and then began to decrease at 500 °C, finallydisappeared above 600 °C. ODMR signal contrast showed the similar trend and was maximized on 400 °C annealed sample.
On the other hand, for high temperature irradiation, the PL intensity was maintained up to 600 °C, and no PL was shown
above 700 °C. The 600 °C irradiated sample showed higher ODMR signal contrast from all other samples. These results
concluded that high temperature irradiation is also useful for spin defect in 2D material.

FIG. 1. Change of PL intensity

FIG. 2. Change of ODMR signal contrast

Acknowledgement
This research is supported by QST President’s Strategic Grant QST Creative Research and JSPS KAKENHI No. 20K05352.
Reference
1
A.Gottsholl et al., Nat Mater. 19, 540 (2020). 2M.Kianinia et al., ACS Photonics. 7, 2147 (2020).
3
M.Capelli et al., Carbon 143, 714 (2019). 4Y.Chiba et al., Mater. Sci. Forum 1004, 337 (2020).

119Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-γ1-01
Error-Disturbance uncertainty relations in Faraday measurements
Le Bin Ho1, and Keiichi Edamatsu1
1Research Institute of Electrical Communication, Tohoku University
binho@riec.tohoku.ac.jp

Introduction
Quantum measurement plays a crucial role in the characterization of physical systems, which elucidate hidden quantum
properties to the classical world. One of its important intrinsic properties is the uncertainty relation which is infeasible tomeasure incompatible observables with arbitrary precision. Heisenberg was first formulated an uncertainty relation between
the position and momentum and later generalized by Arthurs and Kelly
𝜖𝜖𝐴𝐴 𝜂𝜂𝐵𝐵 ≥ 𝒞𝒞𝐴𝐴𝐴𝐴 ,that we call the Heisenberg-Arthurs-Kelly uncertainty. Here, 𝜖𝜖𝐴𝐴 is the error when measuring A and 𝜂𝜂𝐵𝐵 is the disturbancecauses to B measurement, 𝒞𝒞𝐴𝐴𝐴𝐴 = |⟨ψ|[A, B]|ψ⟩|/2, where |ψ⟩ the system state to be measured.
Furthermore, Ozawa [1] and Branciard [2, 3], have considered a rigorous relation reads
22≥ 𝒞𝒞𝐴𝐴𝐴𝐴,𝜖𝜖𝐴𝐴2 𝜎𝜎𝐵𝐵2 + 𝜎𝜎𝐴𝐴2 𝜂𝜂𝐵𝐵2 + 2𝜖𝜖𝐴𝐴 𝜂𝜂𝐵𝐵 �𝜎𝜎𝐴𝐴2 𝜎𝜎𝐵𝐵2 − 𝒞𝒞𝐴𝐴𝐴𝐴

that hereafter we call the Branciard-Ozawa uncertainty, where 𝜎𝜎Λ = �〈Λ2 〉 − 〈Λ〉2 represents the standard deviation of Λ.
Recently, Faraday measurements of spin based on an atom-light interface framework have been studied actively. It hascontributed to our understating of quantum measurement of spin systems and has various applications in quantum metrology
of atoms and spins, quantum information processing, strongly correlated systems, and many-body systems. The Faraday
effect causes the rotation of the polarized light by the spin and thus allows indirect measurement of it via the polarized light.
Such a measurement contains fundamental limits in the sensitivity caused by the quantum nature of light. Likewise, the backaction of the polarized light perturbs the spin state, which causes disturbance on the subsequent measurements of the spin.
In this work, we formulate an atom-light interface scheme for evaluating uncertainty relations.

MethodThe atom is a single spin-1/2 particle interacting with a classical coherent
polarized light. In this way, we derive the error and disturbance, and observe thecyclic oscillations as a result of the Faraday rotation and spin rotation as show in
Fig. 1. Due to the rotation of the polarized light, the square error first is gradually
decreases and then gradually reduces to the minimum at g = π/4 and increases again
at g = π/2. The behavior is then repeated when increasing g. Likewise, the squaredisturbance increases quadratically with the interaction strength and reaches the
maximum at g = π/2 and then decreases to zero for g varies from 0 to π. Thisbehavior is the imprint of the back-action effect on the spin system that disturbs(rotates) the spin on its Bloch sphere.
Similarly, we investigate the case of polarization squeezed light using the phaseFIG. 1. The plot of the square error
space approximation for the light, where the squeezing parameter takes place as ameasurement strength. Larger squeezed parameter means broader Gaussian shapeand square disturbance as functionsin the class of the polarization squeezed state, which is equivalent to “weakof interaction strength.
measurement”, while small squeezed parameter refers to the narrow of Gaussian
shape which results in a strong measurement.
We finally formulate the error-disturbance relations in these cases above and provide that the Heisenberg-Arthurs-Kelly
uncertainty can be violated while the tight Branciard-Ozawa uncertainty [2] always holds.
In conclusion, we evaluated the error, disturbance and uncertainty relations in quantum measurement in the atom-lightinterface framework of Faraday measurements. Our analysis would contribute to the understanding of the error anddisturbance as well as the uncertainty principle in the spin measurements under the atom-light interface framework.
This work was supported by MEXT Q-LEAP Grant Number MXS0118067581.

Reference

M. Ozawa, Error-disturbance relations in mixed states, arXiv:1404.3388 [quant-ph] (2014).
C. Branciard, Proceedings of the National Academy of Sciences 110, 6742 (2013).
3
C. Branciard, Phys. Rev. A 89, 022124 (2014).
1
2

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Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-γ1-02
Hydrogen Annealing Effect on Silicon Optical Waveguide
Yixin Wang1, Kohei Haji2, Shunsuke Abe2, Takuya Inagaki2, Yoshiaki Kanamori3,
Keiichi Edamatsu1, Hirohito Yamada2, Nobuyuki Matsuda2
1

Research Institute of Electrical Communication, Tohoku University

2

Department of Communications Engineering, Graduate School of Engineering, Tohoku University
3

Department of Robotics, Graduate School of Engineering, Tohoku University
wangyixin@quantum.riec.tohoku.ac.jp

Introduction
In recent years, micro-optical waveguides such as silicon optical waveguides have been attracting attention for large-scale
integration of optical circuits. The main cause of propagation loss in silicon optical waveguides is light scattering due to theroughness of the surface of the waveguide core, especially at the side walls [1]. It is expected that the propagation loss of thesilicon optical waveguide will be improved by minimizing the roughness of the silicon surface. Hydrogen annealing has
been reported as one of the effective techniques for smoothing the silicon surface [2]. In this work, we applied hydrogenannealing to a silicon optical waveguide and evaluated the effect on a silicon optical waveguide.

Method and Results
The channel waveguides were fabricated in 220-nm silicon on insulator (SOI) substrates. The resist pattern of the
waveguides was formed by electron beam lithography. The pattern was transferred to silicon by using inductively-coupledplasma based reactive ion etching. The width of the waveguide was 440 nm, while both facets were designed to be as wide
as 3 μm for the effective coupling between a lensed fiber and the waveguide for transverse-electric (TE) mode.
The waveguides chip was then annealed in a hydrogen atmosphere. The temperature, pressure and annealing time were
800 °C, 5 kPa and 2 minutes, respectively. The optical properties of the waveguides were measured with an amplified
spontaneous emission (ASE) light source before and after annealing. FIG.1 shows the waveguide insertion loss as a functionof the waveguide length. In the measurement the input ASE light was filtered by a 1 nm band-pass filter with the center
wavelength of 1550 nm before the waveguide. We see that the propagation loss increased after annealing. By using the cutback method, we estimate that the propagation loss increased by 14.5 dB/cm while the coupling loss of the waveguidedecreased by 1.17 dB/facet. The possible cause of the increase in propagation loss is that silicon may be oxidized at a hightemperature [3] due to the presence of oxygen contained in the exposed SiO2 layer near the waveguide. FIG.2 shows thetransmission spectra of the 1 cm long waveguide before and after annealing. After hydrogen annealing, the insertion loss of
the waveguide increased significantly over the whole measurement range. However, the spectral ripple reduced after
annealing, which may be due to the low Fabry-Perot interference caused by high propagation loss.
-15

-10

Before annealing
After annealing

Transmittance [dB]

-20

-30

Transmittance (dB)

Before annealing
After annealing

-20

-40

-25
-30
-35
-40

-50
0

0.5

1

1.5

-45
1530

1540

1550

1560

1570

Waveguide length (cm)Wavelength [nm]FIG. 1. Insertion loss vs. waveguide length.

FIG.2. Transmission spectra.

Acknowledgement
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067581.

Reference
T. Horikawa et al., MRS Communications 6, 9 (2016).
T. Okatani et al., Opt. Mater. Express 11, 189 (2021).
3
K. Hofman et al., Appl. Surf. Sci. 30, 25 (1987).
1
2

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SE-03A-γ1-03
Wavelength-tunable broadband infrared quantum absorption spectroscopy
in the mid-infrared region 2-5 µm
Masaya Arahata1, Yu Mukai1, Toshiyuki Tashima1, Ryo Okamoto1, and Shigeki Takeuchi1
1

Department of Electronic Science and Engineering, Kyoto University, Japanarahata.masaya.34c@st.kyoto-u.ac.jp

Introduction
Infrared spectroscopy is a powerful technique enabling the noninvasive analysis of the dynamics of the molecular vibration
and rotation modes, and an essential tool for material science and life sciences. However, a conventional infrared
spectrometer has the problems that infrared light sources have large thermal noise and low directivity and infrared detectors
need the cryogenic cooling for the high sensitivity. To overcome these problems, recently, infrared quantum absorption
spectroscopy (IRQAS) has been proposed and experimentally demonstrated [1]. IRQAS enables the spectral measurementin the infrared region only with a low-cost and high-performance visible light source and detector using the quantum
interference between the generation processes of entangled visible-infrared photon pairs. For the broadband IRQAS, somemethods of broadening the generation bandwidths of photon pairs such as the group velocity phase matching were used to
the IRQAS measurement [2]. However, the measurable wavelength ranges of IRQAS were limited to less than 1 µm at most.
Therefore, there are no IRQAS systems covering the mid-infrared (MIR) region 2-5 µm.
Here, we report a wavelength-tunable IRQAS system covering the MIR region 1.9-5.2 µm. The generation wavelengthsof visible-infrared photon pairs can be tuned by rotating a nonlinear crystal with respect to the pump beam to control thephase matching condition [3]. We show the quantum interference is observed in the wavelength region of 2-5 µm just bycontinuously rotating a crystal without the fine realignment. We also experimentally demonstrate the transmission spectrum
measurement of a silica glass sample from the ratio of visibilities of interferogram with and without a sample. Furthermore,
we demonstrate the transmittance measurement with a higher resolution with quantum Fourier-transform infrared
spectroscopy (QFTIR), which enables the measurement in the whole spectrum of photon pairs from the Fourier analysis of
the quantum interferogram [4].

MethodFigure 1 shows our experimental setup of wavelength-tunable IRQAS system with the continuous crystal rotation. A 0.5mm-thick type-I MgO:LiNbO3 crystal with a cut angle of 57.9° is pumped by a CW laser beam with a wavelength of 532
nm. The pump beam is focused into the crystal by a lens (𝑓𝑓=200 mm). Signal (visible) photons with a wavelength of 692
nm and idler (infrared) photons with a wavelength of 2300 nm are generated in the case of the normal incidence of the pumpbeam on the crystal. The SPDC wavelengths can be tuned by rotating the crystal on a rotational stage with respect to thepump beam. When being separated by a dichroic mirror, the signal and pump photons pass through, while the idler photons
are reflected. Then, the signal and pump photons are together reflected back to the crystal by a concave mirror (𝑓𝑓=100 mm).
The idler photons are collimated by a lens (𝑓𝑓=100 mm) and then pass through an ultra-violet fused silica glass window withthe thickness of 1 mm as a sample and are reflected by a mirror on a high-accurate translation stage with the position
repeatability ±2 nm. Then, at the crystal, the second SPDC generation process occurs by the reflected pump beam. Afterbeing collimated by a lens (𝑓𝑓=250 mm) and passing through a long pass filter, an iris as a spatial filter, and a tunable band
pass filter on a translation stage to eliminate the residual pump beam and the background light, signal photons are coupled
to a multimode fiber and then guided to a Si avalanche photodiode and a photon counter to measure the interference of thesingle photon counts. In this presentation, we will report on the results of transmittance measurement of the sample with thewavelength-tunable IRQAS system. This
work was supported in part by the foundationof MEXT Q-LEAP Grant Number
JPMXS0118067634, JST-CREST Grant
Number JPMJCR1674, JSPS KAKENHI
Grant Number 21H04444, Grant-in-Aid for
JSPS Fellows Grant Number 20J23408, and
WISE Program, MEXT.

Reference

FIG. 1. Schematic of wavelength-tunable IR-QAS system. APD: Avalanche photodetector.

D. Kalashnikov, A. Paterova, S. Kulik, and L. Krivitsky, Nat. Photonics, 10, 98 (2016).
C. Lindner, J. Kunz, S. J. Herr, S. Wolf, J. Kießling, and F. Kühnemann, Opt. Express, 29, 4035-4047 (2021).
3
M. Arahata, Y. Mukai, B. Cao, T. Tashima, R. Okamoto, and S. Takeuchi, J. Opt. Soc. Am. B, 38, 1934-1941 (2021).
4
Y. Mukai, M. Arahata, T. Tashima, R. Okamoto, and S. Takeuchi, Phys. Rev. Applied, 15, 034019 (2021).
1
2

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SE-03A-γ1-04
Evaluation of superconducting nanowire single photon detectors
for mid-infrared wavelengths
Yuki Gama1, Toshiyuki Tashima1, Masaya Arahata1, Yu Mukai1, Fumihiro China2, Masahiro Yabuno2,
Satoru Mima2, Shigeyuki Miyajima2, Shigehito Miki2, Hirotaka Terai2, Ryo Okamoto1, and Shigeki Takeuchi1
1

Department of Electronic Science and Engineering, Kyoto University
2

National Institute of Information and Communication Technology
takeuchi@kuee.kyoto-u.ac.jp

Introduction
Recently, single-photon detection in the mid-infrared spectral region has attracted attention as a fundamental techniquefor many technologies such as infrared quantum absorption spectroscopy1,2 and light detection and ranging (LIDAR)3.
However, the single-photon detectors operating in that region suffers from the limited operating wavelength and low
detection efficiency. One of the solutions is to use superconducting nanowire single-photon detector (SNSPD) which
possesses single-photon detection ability and low dark count. Some researchers have developed SNSPDs for the mid-infrared
spectral region and, for example, Verma et al. evaluated the detection performance of SNSPDs fabricated from WSi up to awavelength of 10 𝜇𝜇m4. However, the detection efficiency of such mid-infrared single-photon detectors has not been fully
evaluated so far. In this presentation, we report the experimental evaluation of a NbTiN SNSPD working in the mid-infrared
spectral region. We evaluated dark count and the linearity of detection count by changing the input photon number and thebias current. We also investigated the detection efficiency and obtained the value of 1.20 ± 0.40 % at the wavelength of
4.33 𝜇𝜇m with the bias current of 21.0 𝜇𝜇A.

MethodWe developed a NbTiN SNSPD for the mid-infrared single-photon detection. To improve the sensitivity for the midinfrared single-photons, we fabricated the nanowire with thinner line width of 50 nm instead of typical 80 to 100 nm used
for the SNSPD working in visible and telecommunication spectral region. The SNSPD also has a meander structure and theactive area of 15 × 15 𝜇𝜇m2 (see figure 1(a) inset).
The experimental setup for evaluating SNSPD is shown in FIG. 1(a). We used quantum cascade laser (QCL) with awavelength of 4.33 𝜇𝜇m. The laser power was attenuated to the single photon level with the combination of neutral density
filters and polarizers. The light was coupled to a single mode fiber and passed through a polarization controller which consistsof a polarizer, a half-wave plate, and a quarter-wave plate. Using this system, the input photon polarization was optimized
to maximize the detection count by the SNSPD. The output port of SNSPD was connected to an oscilloscope to observe thewaveform of the output voltage pulse from SNSPD or a pulse counter to obtain the detection count. Here, FIG. 1(b) shows
the waveform of the output voltage pulse from the SNSPD. We set threshold voltage of a pulse counter for each bias current
with this result. Using these voltages, we evaluated dark count and the linearity of detection count by changing the input
photon number and the bias current. In this presentation, we will report the evaluation results in more detail.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067634. JST-CREST Grant Number

JPMJCR1674, Grant-in-Aid for JSPS Fellows Grant Number 20J23408

FIG. 1. (a) Experimental setup for the evaluation of mid-infrared SNSPD. ND filter: Neutral density filter, SMF: Single mode
fiber. The inset shows the schematic of SNSPD. (b) The waveform of the output voltage pulse from mid-infrared SNSPD.

Reference

D. Kalashnikov, A. Paterova, S. Kulik, and L. Krivitsky, Nat. Photonics, 10, 98 (2026).
Y. Mukai, M. Arahata, T. Tashima, R. Okamoto, and S. Takeuchi, Phys. Rev. Applied, 15 (2021).
3
G. Taylor, D. Morozov, N. Gemmell, K. Erotokritou, S. Miki, H. Terai, and R. Hadfield, Opt. Express 27 (2019)4
V. B. Verma et al., APL Photonics, 6, 056101 (2021).
1
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SE-03A-γ1-05
Phase retrieval of joint spectral amplitude
Kemeng Chen and Ryousuke Shimizu
The University of Electro-Communications Fundamental Science and Engineeringc2033074@edu.cc.uec.ac.jp
Introduction
Tailored and energy tunable entangled photons are required rather than polarization entanglement on
quantum information and communication technologies. To characterize the entanglement in a qubit system,
such as polarization entanglement, quantum state tomography has been developed. On the other hand, theevaluation of entanglement for infinite dimension can be achieved by von Neumann entropy obtained by
Schmidt decomposition. However, to implement Schmidt decomposition, the complex probability amplitudeof a two-photon state should be required. Today, we can measure the two-photon spectral or temporal
distributions in 2D space, but it is still challenging to evaluate phase distributions of the two-photon state.
Here we develop Gerchburg-Saxton (GS) algorism to retrieve the phase distribution. In addition, theoriginal intensity data should be corrected by Wiener filter to suppress the noise fluctuation of the retrieved
data.

MethodTo implement GS algorism, we need a pair of data connected with Fourier transformation. Recently we
proposed synthesizing time-frequency entangled photons and verified it by measuring joint spectral andtemporal intensities. We applied GS algorism to these data in the following procedure. At first, we addeda random phase distribution to the frequency domain data and applied fast Fourier transform (FFT).
Then, we extracted the transformed phase distribution in the time domain and reconstructed the joint
temporal amplitude. Next, FFT was performed on the joint temporal amplitude repeatedly applied thesame operation in the time and frequency domains. The transformed amplitudes were compared with themeasured amplitudes and estimated an error. FFT was continued until the error values were below 5%,
and eventually, the retrieved phase distribution was obtained. After the algorism was completed, theresolution of the measured data should be considered to correct the retrieved result. Compared with timedomain data, the resolution in the frequency domain can be ignored and the time domain resolution was
about 200 fs. So, we created ten point-spread functions (PSF) and use the Wiener filter to recorrect theoriginal data. While the noise signal rate is 18, the best retrieval result was shown as the resolution is
197 fs. Figure 2 shows the retrieved phase distribution extracting the area that exceeds 50% of maximum
intensity. Additionally, the retrieved phase distribution can be used on Hong-Ou-Mandle (HOM)
interference conjecture. We also tried to evaluate the visibility of the retrieved result and compare it to
its HOM interference experiment result.
This work was supported by MEXT Q-LEAP Grant Number JPMXS011806924.

Fig. 1 Amplitude on time domain after phaseretrieval and recorrected through point spectral
function with 197 fs resolution

Fig. 2 Retrieved relative phase on frequency
domain corrected by point spectral function
with 197 fs resolution124Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-γ1-06
Temporal shaping of an entangled-photon wave packet by Fourier opticalsynthesis
H. Oshima1, F. China2 M. Yabuno2, S. Miki2, H. Terai2, and R. Shimizu1
1

Univ. of Electro-Comm, 2NICT
o2033021@edu.cc.uec.ac.jp

Introduction
Temporal waveform control of ultrashort optical pulses is based on the one-dimensional Fourier transform relationshipbetween the time and frequency domains, known as "optical synthesis" (OS). On the other hand, we have demonstrated thata two-dimensional Fourier transform (2D-FT) connects two-photon probability distributions of entangled photon pairs intime and frequency domains [1]. Based on this, we have developed manipulating the two-photon wave packet via 2D-FT,
termed "quantum optical synthesis" (QOS) [2]. In this experiment, we created two discrete modes in 2D frequency space.
However, the two-mode manipulation allows us to control the temporal waveform of entangled photons only in sinusoidal
modulations. Our research aims to arbitrarily shape the time-domain structure of two photons with the 2D-FT manner. In
this work, we present the extension of the frequency mode of the entangled photons toward arbitrary waveform shaping.

MethodThe experimental results are shown in Fig. 1. Figure 1 (a) is a two-photon spectral distribution, bidirectionally pumped for
one nonlinear crystal. We can see two discrete frequency modes in the -45° direction. The corresponding temporal
distribution of the two-photon is shown in Fig. 1(b), which has a sinusoidal modulation in the -45° direction. The temporal
distribution with the sub-picosecond resolution was measured by up-conversion detection of single-photon with ultrashortpulses. Figure 1(c) is the measurement results obtained when creating four frequency modes using two nonlinear crystals.
The corresponding time distribution is shown in Fig. 1(d). Setting the relative phase among all the frequency modes to benearly 0, we can see slightly complicated temporal modulation as represented by | cos(2𝜋 × 0.33𝜏− ) + cos(2𝜋 × 1.0𝜏− )|2This work was supported by MEXT Q-LEAP Grant Number JPMXS0118069242.

(a)

(b)

(ｃ)

(ｄ)

Fig.1 Upper plots are the experimental result of two-frequency mode (a) two-photon frequency and (b) temporal
distribution. Lower plots are the experimental result of four-frequency mode (c) two-photon frequency and (d) its
corresponding temporal distributions.
Reference

R.-B. Jin, T. Saito, and R. Shimizu, Phys. Rev. Appl. 10, 034011 (2018).
R.-B. Jin, K. Mihoshima, R. Shimizu et al., APL Photonics 6, 086104 (2021).

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SE-03A-δ1-01
Cryogenic Monolithic Interferometer for Sensing Gravity Gradient
Satoru Takano1, Ching Pin Ooi1, Yuka Oshima1, Yuta Michimura1, and Masaki Ando1
1

Department of Physics, School of Science, The University of Tokyo
satoru.takano@phys.s.u-tokyo.ac.jp

Introduction
Gravity gradient fluctuations are essential observation targets for precise measurement of motion of masses. From theirmeasurement we obtain information about their source behavior. Recently fluctuations at low frequency, around 0.1 Hz, hasbeen aimed for earthquake early alert using transient change of gravity potential [1] and for observation of GWs from mergers
of intermediate-mass black holes [2].
A torsion-bar antenna (TOBA) is a ground-based gravity gradiometer proposed for measurement of gravity gradientfluctuations in such frequencies [2]. It measures torsional rotation angle of horizontally suspended mass(es) induced bygravity gradient fluctuations. Several prototypes and related technologies have been developed [3,4], and now we areplanning to make a 30-cm scale prototype (Phase-III TOBA). Figure 1 shows the design setup of Phase-III TOBA
The goal of Phase-III TOBA is to achieve the strain sensitivity 10-15 / √Hz at 0.1 Hz and demonstrate noise reduction,
especially thermal noise by cooling the suspension system down to 4 K. To achieve this target sensitivity, reduction ofsensing noise of interferometer is necessary. One solution is to make the readout system monolithically. Figure 2 shows thebasic concept of the readout interferometer. We present development plan of the monolithic interferometer and current
situation.
September 12,Method
2018 22:59

WSPC Proceedings - 9.75in x 6.5in

mainpage 5

Monolithic interferometer consists of optical components directly glued on a plate. Thanks to this configuration we canreduce readout noise caused by vibration of optical components, thermal drift, etc. On the contrary, unlike ordinaryinterferometers we cannot adjust optics after gluing. Therefore, its construction requires special care. Recently the technology
of construction has been well studied and validity of noise suppression has been proved in many fields.
Monolithic interferometers have been studied for applications in room temperatures. However, for TOBA case theinterferometer is under cryogenic environment. Therefore, we have to revise usual way of construction of monolithic
interferometer in order to survive in cryogenic temperatures. We have tested alternatives suitable for cryogenic
environment
5
and the results will be reported in the presentation.

-12

10

total
Shot noise
Radiation pressure
RotationalTM
seismic(silicon)
Seismic cross-coupling
Suspension thermal (4K)
Bar thermal (4K)
Gas thermal (10-7 Pa)

Cryogenic
Temp.

√
Strain [/ Hz]

-13

10

-14

10

OpticalFiber

Laser2

Laser1

10-15

Monolithic Bench

10-16

Coupler
10-17
-2
10

(a)

FIG. 1. Setup of Phase-III TOBA.

Fig. 3.

-1

10Frequency [Hz]

0

10

(b)

Rotational
MotionFIG. 2. Schematic of readout interferometer.

Beat
Signal/ 19(a) The design of phase-III TOBA. (b) The target sensitivity of phase-III TOBA.

Acknowledgement
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118070351.

The suspended pendulums will be kept at the cryogenic temperature of 4 K to
reducethermal fluctuations. The pulse-tube cryocooler is installed in the vacuum
Reference
1
2chamber,connected
to201,
the1416-1425
intermediatethepurewires (2010)
J. Harms et andal., Geophys.
J. Int.,(2015) masses
M. Andovia
et al.,
Phys.
Rev.aluminum
Lett., 105, 161101
3
4K.
Ishidoshiro
et
al.,
Phys.
Rev.
Lett.,
106,
161101(2011)
A.
Shoda
et
al.,
Phys.
Rev.
D,
95,
082004(heatlinks). The test masses are cooled via thermal radiation from the surface(2017)(300 K → 50 K) and heat conduction of the suspension wire (50 K → 4 K). The
suspension wires will be made of silicon or sapphire, which are known to have highQ values (∼ 108 ) at cryogenic temperatures 13 .
The six seismometers and the hexapod actuators are placed at the top stage tokeep it isolated from the ground by active feedback control. An additional ground126

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-δ1-02
Suspension Noise measurements of Cryogenic Torsion Pendulums with
Crystalline Fibres
Ching Pin Ooi1, Satoru Takano1, Yuka Oshima1, Yuta Michimura1, and Masaki Ando1
1

Department of physics, School of Science, The University of Tokyo
ooichingpin@g.ecc.u-tokyo.ac.jp

Introduction
Thermal noise in mechanical sensors are a fundamental noise source and a limit for sensitivity. Torsion Bar Antenna(TOBA), a proposed ground-based gravity gradiometer targeting the frequencies 0.1 - 10 Hz [1], naturally has this noise
source. TOBA utilises torsion pendulums at high sensitivities to detect these gravitational fluctuations, which can be used
for early earthquake detection [2] and sensing the gravitational waves from the mergers of intermediate mass black holes [1].
In this work, we study the suspension noise of torsion pendulums, and study how the use of two key technologies, cryogenic
temperatures and crystalline fibres can reduce it.
To quantify the suspension thermal noise, we focus on measuring the Q factor, with which we can calculate the suspension
thermal noise, given other parameters such as the temperature, and the relevant frequencies.

MethodA copper beryllium torsion pendulum with a sapphire suspension fibre was placed in a cryogenic chamber. The Q factorof the torsion pendulum was then measured via the ringdown method as the setup was thermally cycled from room
temperature to 4 K and back. The radial position of the torsion pendulum was measured using an optical lever. The torsion
pendulum was excited using coil-coil actuators, to allow for the ringdown measurement to take place.

Q vs Temp for sapphire
100000
Cooldown

Q

Warm up

10000

1000
0

50

100

150

200

250

300

Temp (K)FIG 1. Graph of Q vs Temperature for a sapphire suspension fibre. The

Q values ranged from 3 000 to 70 000 at 4 K, showing a great
dependence on temperature, and follows the expectation that Q should
increase at cryogenic temperatures. The resonance frequency was at 6
Hz, within the TOBA targeted frequencies of 0.1 – 10 Hz.

FIG 2. Picture of torsion pendulum, with attachedmirror for optical lever readout, and coils for coilcoil actuation. The sapphire fibre used forsuspension is 1 mm in diameter

Acknowledgments

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

127

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-δ1-03
Angular Sensor with a Coupled Cavity for Gravity Gradient Sensing
Yuka Oshima1, Satoru Takano1, Ching Pin Ooi1, Yuta Michimura1, and Masaki Ando1
1

Department of Physics, University of Tokyoyuka.oshima@phys.s.u-tokyo.ac.jp

Introduction
TOrsion-Bar Antenna (TOBA) is a highly sensitive gravity gradient sensor using torsion pendulums [1]. The resonant
frequency of torsional motion is ~1 mHz, therefore TOBA has good design sensitivity in low frequencies (0.1 – 10 Hz). A
prototype detector Phase-III TOBA with a 35 cm-scale pendulum is under development to demonstrate noise reduction [2].
The target sensitivity is set to 10-15 /√Hz at 0.1 Hz. Phase-III TOBA can detect earthquakes with magnitude 7 or larger within
10 seconds from 100 km distance, therefore Phase-III TOBA is useful for gravity-based earthquake early warning [3]. To
achieve our target sensitivity, we need to measure the pendulum rotation precisely. We propose a coupled wavefront sensor
as an angular sensor for Phase-III TOBA. We show the principle and experimental demonstration status of a coupled
wavefront sensor.
MethodFor a conventional wavefront sensor, we build a linear cavity with two mirrors (FIG. 1. Top). When a mirror tilts, a partof the zero-order Hermite-Gaussian (HG) modes converts into the first-order HG modes. We detect it as angular signal. In
the cavity, the first-order HG modes are anti-resonant since they get non-zero Gouy phase shift compared to the zero-order
HG modes.
A coupled wavefront sensor is a new wavefront sensor using an optical coupled cavity. In our method, we put one more
mirror behind a main cavity and build an auxiliary cavity (FIG. 1. Bottom). An auxiliary cavity can compensate Gouy phaseof main cavity, therefore the zero-order and the first-order HG modes are resonant simultaneously. As a result, angular signal
is enhanced in the main cavity.

FIG. 1. Top: The schematic of a conventional wavefront sensor. Bottom: The schematic of a coupled wavefront sensor.

Acknowledgments
This work was supported by MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) Grant Number
JPMXS0118070351.
Reference1
M. Ando et al., Phys. Rev. Lett., 105, 161101 (2010).
2
T. Shimoda et al., International Journal of Modern Physics D, 29, 1940003 (2020).
3
T. Shimoda, PhD thesis, The University of Tokyo (2019).

128

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-δ1-04
Towards sensitive accelerometers with levitated single nanoparticles
K. Aikawa1, M. Kamba1, H. Kiuchi1, K. Okuda1, N. Suyama1, and R. Shimizu1
1

Department of Physics, School of Science, Tokyo Institute of Technology
aikawa@phys.titech.ac.jp

Introduction
Single nanoparticles levitated in vacuum are a promising platform for sensitive accelerometers as well as for exploring
macroscopic quantum physics. Cooling of their motion to the ground state of a trapping potential, corresponding totemperatures of about 10 µK, has recently been demonstrated. We plan to use levitated nanoparticles as sensitive
accelerometers. For this purpose, we develop two experimental setups: one with an optical lattice, and one with an ion trap.
In this presentation, we briefly introduce the latest results from both setups.

MethodIn a setup with an optical lattice, we find that the phase noise of the trapping laser has a crucial impact on the motion along
optical lattice. When the phase noise as well as the intensity noise are decreased, the center-of-mass motion along the opticallattice is cooled to near the ground state via electric feedback cooling1. The position sensitivity demonstrated in our setup isbetter than 10 fm⁄√Hz, suggesting that nanoparticles is a promising system as a sensitive accelerometer.
In a setup with an ion trap, we design and fabricate a novel electrode geometry allowing us to place a high-numericalaperture lens, required for observing the motion of nanoparticles, close to the electrodes. In this ion trap, we demonstrate thestable confinement of nanoparticles and observe their three-dimensional motion via the high-numerical-aperture lens. Dueto the low oscillation frequency of nanoparticles in the ion trap, the ion-trap setup is also a promising setup for the sensitive
detection of acceleration.

Reference

M. Kamba, H. Kiuchi, T. Yotsuya, and K. Aikawa, Phys. Rev. A 103, L051701 (2021).

1

129

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-δ1-05
Interferometric gyroscope using slow and continuous atomic beam
Tomoya Sato1, Ryotaro Inoue1, Mikio Kozuma2,11

Institute of Innovative Research, Tokyo Institute of Technology

2

Department of Physics, School of Science, Tokyo Institute of Technology
sato@qnav.iir.titech.ac.jp

Introduction
A self-localization method, which does not rely on external signals, complements methods such as satellite positioning by
the GPS signal, ensuring safety and improving estimation accuracy by hybridization. Such a method is also essential fornavigation in environments where other methods cannot be applied, for example, under the sea.
One can estimate their position by integrating the angular velocity and acceleration in time. Such a self-localization method
consists of a gyroscope and accelerometer is called inertial navigation. The accuracy of the current high-end inertial
navigation system is dominated by the performance of the gyroscope, which employs the optical Sagnac effect, such as thering laser gyroscope. The magnitude of the phase difference between counter-propagating waves for the Sagnac
interferometer is inversely proportional to the product of wavelength and velocity of the wave. Thus, the matter-wave
interferometer is a promising way to improve the phase sensitivity of the gyroscope since the wavelength and velocity of thematter-wave are much smaller than those of the light wave [1]. We aim to develop the matter-wave gyroscope utilized by
the slow and continuous atomic beam interferometer, which can be mounted on a vehicle.

MethodA pair of atomic beams which is extracted from the 2D+MOT [2] is introduced into the interferometer region, where threepairs of counter-propagating Raman beams form the π/2-π-π/2 Mach-Zehnder type interferometer [3]. The Sagnac effectcauses the sinusoidal variation between populations of internal states of the atom as a function of the angular velocity on the
Sagnac loop. Thus, the rotation of the system can be deduced from the phase shift in the interference signal.
The measured phase shift reflects the rotation of the system, but at the same time, acceleration and environmental
disturbances also change the phase. It is necessary to eliminate these effects for accurate measurement. It can be achievedby using a pair of atomic interferometers with atomic beams that share Raman lights and travel in opposite directions [4].
Since the sign of phase shift induced by the rotation depends on the velocity vector, but that induced by the spurious effectis not. By measuring the differential phase shift between two interferometers, we can extract the phase shift caused by rotation
while eliminating that caused by common-mode noises.
We measured the phase shift in the interference signal as a function of the tilting angle of the optical table on which theapparatus was installed (FIG.1). The linear phase shift due to the gravitational acceleration was observed as a function of thetilting angle. It was also confirmed that the common-mode rejection reduced that linear phase shift. The remaining phaseshift after the rejection was consistent with the shift caused by the angular velocity of the Earth's rotation. To the best of ourknowledge, this is the first demonstration of a gyroscope using the slow and continuous atomic beam.

FIG. 1 Phase shift in interferometer due to the acceleration and rotation. Dashed lines indicate theoretical values.
This work was supported by JST-Mirai Program, Grant Number JPMJMI17A3 and COI-NEXT, Grant Number
JPMJPF2015.

Reference

J. F. Clauser, Physica B, 151, 262 (1988).
K. Dieckmann, R. J. C. Spreeuw, M. Weidemüller, and J. T. M. Walraven, Phys. Rev. A, 58, 3891 (1998).
3
M. Kasevich and S. Chu, Phys. Rev. Lett, 67, 181 (1991).
4
T. L. Gustavson, P. Bouyer and M. A. Kasevich, Phys. Rev. Lett, 78, 2046 (1997).
1
2

130

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-δ1-06
Development of a quantum gyroscope based on a single ion trapping techniques
Ryoichi Saito1,2, and Takashi Mukaiyama1,2
1

Graduate school of Engineering, Osaka University
2

QIOB, Osaka University

r_saito@ee.es.osaka-u.ac.jp
Introduction

Atoms in a coherent superposition of different momentum states enable high-precision measurement ofphysical quantities. Matter-wave interferometers typically exploit entanglement between the internal
state and the motional state of matter. The accumulated matter-wave phases for different paths are
obtained from the interference signal of the internal states after the closing pulse of the interferometer.
In order to achieve precise sensing, exquisite control of internal and external states of individual quantais essential. Atoms and ions are ideal matter for such use since they provide us with the precise controlof their quantum states using optical means. So far, neutral atoms have been used for various sensing
applications such as detection of gravitational acceleration1, electric and magnetic field2, rotation3 and soon. On the other hand, a trapped ion has not been considered for a platform to realize sensing of external
perturbations until recently. This may partly be because of the difficulty in realizing a large interference
area due to the tight confinement of the ion trap, which is inextricably linked with the advantage of acapability of stable trapping. Quite recently, Campbell and Hamilton proposed to utilize a trapped ion fora precise rotation sensing application. In the proposal, a trapped ion in a circular motion constructs a
Sagnac interferometer. By taking an arbitrary number of ion rotations, the sensitivity of the rotation
sensing can be tuned, and the ions with multiple circular motions may provide us with a large interference
area and a compact physical size at the same time.

MethodThe Sagnac interferometer, which utilizes the single trapped
ion, is realized by circularly propagating wave packet of the ion.
The protocol to generate the two-dimensional circularinterferometer is as below. First, we apply the microwave half
pi pulse to the ion in a two-dimensional isotropic potential for
creating the superposition of the internal spin state. Then, we
irradiate a mode-locked laser at 355 nm to apply the momentum
kick, depending on the internal spin state, to generate the onedimensional interferometer5. After the generating spin-motion
entangled state by spin-dependent momentum kick, nonadiabatic trap potential shift in a perpendicular direction to themomentum kick is applied by step voltage to the electrode6.
Then, the wave packet of the ion propagates an elliptical orbit.
The rotation of the system produces the path difference between
clockwise and counterclockwise. The phase shift of the ion
matter-wave due to the rotation is measured by the detection
probability of the internal state.
FIG. 1. Schematic diagram of rotation sensing
In the presentation, we will talk about our experimental
using a trapped ion
detail and the current achievement.

Reference

M. Kasevich and S. Chu, Phys. Rev. Lett. 67, 181 (1991).
K. Zeiske, G. Zinner, F. Riehle, and J. Helmcke, Appl. Phys. B 60, 205 (1995).
3
T. L. Gustavson, P. Bouyer, and M. A. Kasevich, Phys. Rev. Lett. 78, 2046 (1997).
4
W. C. Campbell and P. Hamilton, J. Phys. B: At. Mol. Opt. Phys. 40
5
A. Shinjo, M. Baba, K. Higashiyama, R. Saito, and T. Mukaiyama, Phys. Rev. Lett. 126, 153604 (2021).
6
R. Saito and T. Mukaiyama, Phys. Rev. A 104, 053114 (2021)..
1
2

131

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SE-03A-δ1-07
Exponentially Enhanced Quantum Metrology by Quenching SuperradiantLight-Matter Systems Beyond the Critical Point
Karol Gietka, Lewis Ruks, and Thomas BuschOkinawa Institute of Science and Technology, Quantum Systems Unit
Karol.Gietka@oist.jp
Introduction
We present a quantum metrology protocol which relies on quenching a light-matter system exhibiting a superradiantquantum phase transition beyond its critical point. In the thermodynamic limit these systems can exhibit an exponential
divergence of the quantum Fisher information in time, whose origin is the exponential growth of the number of correlated
photons on an arbitrarily fast time scale determined by the coupling strength. This provides an exponential speed-up in thegrowth of the quantum Fisher information over existing critical quantum metrology protocols observing power law behavior.
We demonstrate that the Cramer-Rao bound can be saturated in our protocol through the standard homodyne detection
scheme. We explicitly show its advantage in the archetypal setting of the Dicke model and explore a quantum gas coupled
to a single-mode cavity field as a potential platform. In this case an additional exponential enhancement of the quantum
Fisher information can in practice be observed with the number of atoms N in the cavity, despite existing works suggestinga requirement of N-body coupling terms.

Reference

K. Gietka, L. Ruks, T. Busch, arXiv, S. Schmitt, Science, 2110:04048, (2021).

132Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α2-01
Three-layered Magnetically Shielded Room for Ultrahigh-sensitivity
Quantum Sensing of Biomagnetic Signals
Motofumi Fushimi1, Akihiro Kuwahata2, Shinichi Chikaki1,
Takao Yamaguchi3, Yuuki Niwa3, and Masaki Sekino1
1

Graduate School of Engineering, The University of Tokyo
2

Graduate School of Engineering, Tohoku University
3

Ishida Ironwork’s Co., Ltd.

motofumi-fushimi@g.ecc.u-tokyo.ac.jp
Introduction
Measurement of biomagnetic fields generated from biological tissues such as the brain and heart has attracted great attention
since it enables us to observe physiological activities of living organisms. Quantum sensers such as the optically pumped
atomic magnetometer and the nitrogen-vacancy center in diamond have achieved ultrahigh-sensitivity sensing of magnetic
fields and opened the field of biomagnetic signal sensing at room temparature. However, to measure the extremely weakbiomagnetic signals (typically at the order of picotesla), a magnetically shielded room (MSR) that prevents the ambient
magnetic field (typically at the order of microtesla) from contaminating the target biomagnetic signals is essential [1].
In this study, we developed an MSR made of three-layered permalloy plates and measured its shielding factor to validate theefficacy of the shield in biomagnetic sensing such as magnetoencephalography (MEG) of small animals.

Methods

Figure 1 shows the developed MSR consisting of three layers of permalloy plates and one layer of aluminum plate forshielding high frequency fields. The inside dimension of the MSR is 3 m x 2 m x 2 m, and thus available for wide range of
biomedical applications including human subjects. For the measurement of the magnetic fields, we used a highly sensitive
fluxgate sensor (502A, APPLIED PHYSICS SYSTEMS). While applying the external AC magnetic fields at 0.1-100 Hz,
we evaluated the shielding factor defined here as the ratio of magnetic field strength inside to outside the MSR.

FIG. 1. Three-layered MSR developed in this study.

FIG. 2. The shielding factor at each four side of the MSR

Results and Discussion

Figure 2 shows the shielding factor of four each side of the MSR. The shielding factor increases with frequency thanks tothe aluminum layer and the factor of about 104-105 is achieved at 10 Hz, which corresponds to the frequency of the alphawave of humans. The shielding factor measured at the front side is relatively low. This is because the door of the shield
deteriorates the effect of the aluminum layer. Although the MSR greatly suppresses the magnetic field, an additionalshielding factor of about 102 is required to achieve the sensing of picotesla-scale biomagnetic signals. Introducing an active
cancelling coil in the MSR would provide the sufficient shielding capability [2,3], evaluation of which is our future work.

Acknowledgements

This work was supported by MEXT Quantum Leap Flagship Program (Q-LEAP) Grant Number JPMXS0118067395.

References

T. J. Sumner et al., J. Phys. D: Appl. Phys., 20, 1095 (1987).
K. Harakawa et al., IEEE Trans. Mag., 32(6), 5256-5260 (1996).
3
E. Boto et al., Nature, 555, 657-661 (2018).
1
2

133

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SE-03A-α2-02
Super-resolution in nano-NMR
Nicolas Staudenmaier1, *, Santiago Oviedo-Casado2, Anjusha Vijayakumar-Sreeja1, Genko Genov1,
Alex Retzker2 and Fedor Jelezko1,4
1

Institute for Quantum Optics, Ulm University, D-89081 Ulm, Germany

2

Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Givat Ram, Israel
4

Center for Integrated Quantum Science and Technology, Ulm University, D-89081 Ulm, Germany*nicolas.staudenmaier@uni-ulm.de

Introduction
There is increasing interest in reducing the size of NMR and MRI devices to gain new insights to processes on thenanoscale. These include for example NMR studies of single cells, neurons1, or surfaces and surface chemistry2. Nitrogenvacancy (NV) centers in diamond show to be promising sensors for such applications. In the past years nano- to microscale
NMR has been proven using single3, 4 or ensemble NV centers5. Importantly, unlike in conventional NMR, signal pickup
with NV centers does not depend on the strength of an applied external magnetic field, allowing for the acquisition of
information-rich spectra from zero and low-field6 as well as high-field NMR. On the other side nanoscale NMR resorts tostatistical nuclear spin polarization rather than directional such as thermal polarization. For that reason, spectral resolution islimited by diffusion of a liquid sample in the detection volume. However, there is theoretical evidence that the signal
correlation does not drop off exponentially but that there is a polynomial tail for longer times allowing a sharp peaked signal
in the spectrum7, 8. We will show experimental evidence that promotes such a model that overcomes any resolution limit andultimately enables super-resolution of signals with nearby frequencies.

MethodExperimental measurements are done on a homebuilt confocal microscope using single shallow NV centers located about
10nm below the diamond surface. Hydrogen nuclear spins, naturally present in the used immersion oil, are sensed via anuclear spin sensitive dynamical decoupling sequence in combination with the quantum heterodyne (Qdyne) measurement
protocol9, that correlates all individual readouts. From the data the autocorrelation of the NMR signal is obtained andanalyzed using different statistical tools.

References
1
M. Grisi et al., Sci. reports 7, 44670 (2017).

G. A. Somorjai and Y. Li, Proc. Natl. Acad. Sci. 108, 917–924 (2011).
H. J. Mamin et al., Science 339, 557-560 (2013).
4
T. Staudacher et al., Science 339, 561-563 (2013).
5
D. Glenn et al., Nature 555, 351–354 (2018).
6
M. Ledbetter et al., J. Magn. Reson 199, 25-29 (2009).
7
D. Cohen et al., Sci. Rep. 10, 5298 (2020).
8
S. Oviedo-Casado et al., Sci. Rep. 10, 19691 (2020).
9
S. Schmitt et al., Science 356, 832-837 (2017).
2
3

134

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SE-03A-α2-03
Sensitivity of weight imaging using a hybrid system based on piezoactive
magnetic material and diamond quantum sensor
Ryota Kitagawa1, Shunsuke Nagata1, Soki Urashita1, Keigo Arai1,2, Kosuke Mizuno1,
Hitoshi Ishiwata1, 2, Yota Takamura1,
Takayuki Iwasaki1, Shigeki Nakagawa1, and Mutsuko Hatano1
Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2
PRESTO, Japan Science and Technology Agency
kitagawa.r.ab@m.titech.ac.jp
Introduction
Imaging weight over multiple length scales from single cells to biological tissues, remaining a key challenge, introduces
a new modality for studying biological systems. Such a high dynamic range in length scale can be realized by a hybrid sensor
based on magnetostrictive(MS) magnetic material [3] and nitrogen-vacancy (NV) centers in diamonds [4]. To detect theweight of human egg cells, the weight accuracy of ~ 1 Pa is required. In this research, we evaluated the weight sensitivity of
the hybrid system. We measured weight-to-magnetic field conversion efficiency and magnetic field sensitivity.
MethodWe fabricated a hybrid sensor by gluing a MS magnetic material of a SmFe2 thin film[3], deposited on an ultra-thin quartz
substrate, and NV centers in a diamond film deposited on a type-Ib diamond (111) substrate (Fig. (a))[5]. Various weight
was applied through a rivet in an area of 3.1 mm2 by changing the number of calibrated weights (0 ~125 kPa). Due to theinverse MS effect, weight is converted into the rotation of magnetization in the MS layer (Fig. (b)). This rotation induces achange in the stray magnetic field, imaged by NV centers via optically-detected magnetic resonance (ODMR). We imaged
the magnetic field by continuous-wave ODMR while changing the weight. One pixel of the image is (4.9 µm)2.
ResultFig. (c) shows a magnetic field image at 0 kPa. We successfully imaged the magnetic field from SmFe 2. Fig. (d)shows the Bz-pressure dependence of one pixel. Weight-to-magnetic field conversion efficiency was 70 nT/kPa. The
estimation accuracy of Bz was about 2 µT per one pixel. Thus, the estimation accuracy of weight was 28 kPa.
Depositing SmFe2 on the NV center will improve the conversion efficiency by an order. Further improvement ofmagnetic field sensitivity is required, such as utilizing pulsed measurement, improvement of coherence time andgeneration rate of NV center, and spatial integration of the ODMR signal.
This work was supported by MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) Grant Number
JPMXS0118067395.
Reference
Vegas, AQ-11,5 Nov. 2019.
[1] G. Popescu et al., Lab Chip 14, 646-652 (2014).
[4] J. Cai et al., Nat. Commun. 5, 1 (2014).
[2] D. Martínez-Martín et al., Nature 550, 500-505 (2017)[5] K.Tahara et al., Appl. Phys. Lett. 107, 193110 (2015)[3] Y. Takamura, et al.,2019 Annu. Conf. on MMM, Las
1Fig. (a) Setup of hybrid weight imaging system. (b) Weight-dependent rotation of magnetization due to inverse MS effect.
(c) Magnetic field image at 0 kPa. The upper light area is off MS film. The scale bar is 100 µm. (d) Bz-pressure dependence of a
selected point. Error bar is the ±1.96𝜎 confidence interval. Weight-to-magnetic field conversion efficiency was 70 nT/kPa.

135

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SE-03A-α2-04
Study on electron spin control method for high-sensitivity diamond quantum sensor
Hiroyoshi Tomioka1, Yuji Hatano1, Takeharu Sekiguchi1, Keigo Arai1, Hiromitsu Kato2,
Shinobu Onoda3, Takeshi Ohsima3, Takayuki Iwasaki1, and Mutsuko Hatano1
1

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
23

National Institute of Advanced Industrial Science and Technology

National Institutes for Quantum and Radiological Science and Technology
tomioka.h.ac@m.titech.ac.jp

Introduction
A diamond quantum sensor utilizing the NV center, a paramagnetic defect composed of nitrogen and vacancy in diamond,is expected to be applied to life-science [1] and automotive fields due to its high sensitivity and room temperature operation.

However, further improvements in DC-field sensitivity and miniaturization are demanded for practical applications.

To achieve such improvements, we focus on CE (continuously excited)-Ramsey method [2] as an alternative to theconventional method of continuous-wave optically detected magnetic resonance (CW-ODMR) or regular Ramsey.

Methods

In CE-Ramsey measurement, the excitation light is continuously applied while the microwaves are pulsed to control theelectron spin states. Our experimental setup is shown in Fig. 1(a). In this study, we performed CW-ODMR, CE-SQ (single
quantum)-Ramsey, and CE-DQ (double quantum)-Ramsey measurements to compare the magnetic sensitivities between
them. We also estimated the shot noise limited sensitivities of CW-ODMR and CE-SQ-Ramsey methods. For this calculation,
we solved the rate equations involving only five levels [3]: two ground states, two excited states, and a metastable state. The
diamond sample used was grown by CVD (100 µm thickness) using 12C-enriched methane on a IIa substrate with a (111)
surface, followed by electron beam irradiation (5 × 1017 cm−2 ) and annealing.

Results and discussion

The magnetic sensitivities obtained by CW-ODMR, CE-SQ-Ramsey, and CE-DQ-Ramsey methods are plotted in Fig.
1(b). The CE-SQ-Ramsey and CE-DQ-Ramsey measurements showed better magnetic sensitivities than CW-ODMR for themodulation frequency between 10 and 90 kHz. Fig. 1(c) shows the calculation result of the shot noise limited sensitivity.
This sensitivity is better for CE-SQ-Ramsey than CW-ODMR at high modulation frequencies (above 20 kHz). In addition
to the sensitivity improvement, CE-Ramsey is suitable for miniaturization because it does not require pulsing of a highpower laser, which is essential for the regular Ramsey. Therefore, we expect it to be used for applications such as battery
monitoring in electric vehicles.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395.

Reference[1] J. F. Barry et al., Proc. Natl. Acad. Sci. USA, 113, 14133 (2016). [2] C. Zhang et al., Phys. Rev. Appl. 15, 064075(2021).
[3] K. Jensen et al., Phys. Rev. B 87, 014115 (2013).

(a)

(b)

(c)

FIG. 1. (a) Schematic of the experimental setup. (b) Comparison of the experimental magnetic sensitivities with different
modulation frequencies. (c) Comparison of the shot noise limited sensitivities calculated by using five level model withdifferent modulation frequencies.

136Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α2-05
Optically detected magnetic resonance spectra of silicon vacancies
in 4H-SiC with different temperatures
S. Motoki1, 2, S.-I. Sato2, Y. Masuyama2, Y. Yamazaki2, Y. Hijikata1, T. Ohshima2
1 1

Science and Engineering, Course in Electrical and Electronic Systems, Saitama University
2

National Institutes for Quantum Science and Technology
E-mail: s.motoki.639@ms.saitama-u.ac.jp

Introduction
Silicon vacancy (VSi −) centers in silicon carbide have attracted attention because of their potential applications to quantum
sensors (high-sensitivity magnetic field and temperature sensors). VSi − centers are also expected to be used for magnetic
sensors under harsh environments such as space and undergrounds, since they have structural stability and the potential ofhigh-fidelity spin manipulation at high temperatures1. To realize VSi − based magnetic sensors operating at high temperature,understanding of optically detected magnetic resonance (ODMR) in the ground states of VSi − centers, which is the basic
principle of magnetic sensing, is crucial. In particular, the effects of temperature on the ODMR spectra are less wellunderstood. Here, we demonstrate the potential of VSi − magnetic sensors at high temperatures by showing the ODMR
spectra with different temperatures. We also systematically investigate the effects of high energy electron irradiations on the
ODMR spectra of formed VSi − centers. The concentration of VSi − centers increases with increasing electron irradiation dose,
resulting in the enhancement of sensitivity, but increase in undesired defects which can cause decoherence is also expected.
Hence, the effects of electron irradiation dose should be clarified to obtain better sensitivity of VSi − based magnetic sensors.
MethodHigh purity semi-insulating (HPSI) 4H-SiC was irradiated with 2 MeV electrons at room temperature up to the dose of
3×1018 cm-2 to form VSi − centers. The samples were then thermally annealed at 873 K for 30 minutes in vacuum to obtainstability during measurements at high temperature. FIG. 1 shows ODMR spectra of VSi − centers in 4H-SiC at different
temperatures. The 785 nm laser at 40 mW was used for excitation and the emitted photons above 900 nm were collected by
an InGaAs photo detector. Under zero magnetic field, a resonant peak at 70 MHz due to zero-field splitting of VSi − groundstates appeared even at 600 K, being reduced with increase temperature. The resonant peak was split into two peaks byapplying external magnetic field (Zeeman splitting).
These results suggest that spin manipulation of VSi −centers is possible at 600 K and thus high temperature
operation of VSi − based magnetic sensor is feasible. At
the presentation, the mechanism of change in ODMR
spectra with different temperatures is discussed. In
addition, the relationship between the ODMR spectra
and the electron irradiation dose is reported.
Acknowledgement
This presentation is based on results obtained froma NEDO Feasibility Study Program (Uncharted
Territory Challenge 2050). Part of this study was
supported by MEXT Q-LEAP grant numbers
JPMXS0118067395, and JSPS KAKENHI grant
numbers 20H00355, and was carried out within theframework of IAEA CRP F11020.
Reference
1
H. Kraus et al., Sci. Rep. 4: 5303 (2014).

FIG. 1. ODMR spectra of VSi − centers in
4H-SiCatdifferent
temperatures.
Experimental data (symbols) are fitted by
the Lorentzian function (solid lines).

137Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-α2-06
High efficiency formation of NV center inside diamond by femtosecond laser
Ryusei Yanoshita1, Torataro Kurita1, Yasuhiko Shimotsuma1,
Masanori Fujiwara2, Norikazu Mizuochi2, Masahiro Shimizu1, Kiyotaka Miura1
1

Department of Material Chemistry, School of Engineering, Kyoto University
2
Institute for Chemical Research, Kyoto University
yanoshita.ryuusei.66a@st.kyoto-u.ac.jp

Introduction
The ensemble of NV centers, consisting of impurity nitrogen and adjacent vacancies in diamond, are expected as
quantum sensors due to their long coherence time and possible coherent control of a single spin at room temperature[1]. Although the single NV center formation by femtosecond laser irradiation has been reported [2], the formation
mechanism is not fully understood. Especially, the transformation of diamond to graphite [3] and the effective laser
irradiation parameters for the formation of NV center ensemble remain unexplored. More recently, we havedemonstrated that the pulse width and the number of pulses are effective to generate a higher density NV center
ensemble [4, 5]. Here we report on the relation between the impurity nitrogen concentration and the laser irradiation
parameters for the NV center formation. In particular, we focused on the efficiency of the NV center formed by the
femtosecond laser irradiation with different pulse repetition rates.
MethodA femtosecond laser beam with a central wave length of 800 nm (bandwidth 37 nm) and a pulse width of 60 fs was
focused in a diamond sample through the objective lens (50× NA 0.80). The focus was located at a depth of 50 µm below
the sample surface. In the experiments, two diamonds with different nitrogen concentrations (Sample A: CVD synthesizedType IIa diamond, [N]  1 ppm, Sample B: HPHT synthesized Type Ib diamond, [N]  33 ppm) were used. The laser
pulses were irradiated from the normal to the (100) plane. To reveal the effect of the impurity nitrogen concentration, thePL intensity originated from the NV- center ranging from 640 nm to 660 nm between the different diamond samples wascompared. Since the threshold of NV center formation by the femtosecond laser irradiation depends on the impurity
nitrogen concentration, we tuned the pulse energy (Ep) according to the samples. The Ep between 50 nJ and 200 nJ wasapplied for sample A, on the other hand, the Ep was set to 2000 nJ for sample B. Other laser parameters such as the pulse
width (60 fs), pulse repetition rate (250 kHz), and the number of pulses (2.5105) were set the same. Table 1 shows the
PL intensity (IPL) normalized by that in the unirradiated region. Despite the fact that the Ep for sample A was lower thanthat for sample B in all experiments, the PL intensity for sample A reached approximately 4.4 times higher than that for
sample B. Assuming the PL intensity is proportional to the NV center concentration, this result indicates that the formation
efficiency for the NV center is high when the impurity nitrogen concentration is low. We have also confirmed theformation efficiency of the NV center by the femtosecond laser irradiation with various pulse repetition rates ranging
from 5 kHz to 250 kHz. In the laser experiments, the irradiated number of pulses was set to be 2.5105 pulses by changing
the irradiation time. Fig. 2 shows the normalized PL intensity was changed by the pulse repetition rate, despite that thesame total pulse energy was irradiated. In particular, the NV center concentration decreased at 10 kHz or less and 100
kHz or more. In the case below 10 kHz, corresponding to the pulse interval of 100 s, such timescale is quite longer thanthat for thermalization and the lifetime of the exciton in diamond (~ 1 s). Furthermore, the decrease of NV center
concentration at 100 kHz or more could be interpreted in terms of the annihilation of NV center or the transformation into
the different defects such as H3 center.
Table1. Normalized PL intensity of NV centerin two different types of diamonds.

ReferenceType

E p [nJ]

I PL

Ib

2000

8.21

IIa

50

4.05

IIa

100

17.4

IIa

200

35.8

Fig. 2. Normalized PL intensity of NV center induced by the
femtosecond laser pulses with various pulse repetition rates.

[1] A. Gruber, et al., Science 276 2012 (1997).
[2] Y. Chen, et al., Nat. Photonics 11 77 (2017).
[3] M. Sakakura, et al., J. Laser Micro/Nanoeng. 11 346 (2016).
[4] T. Kurita, et al., Appl. Phys. Lett. 113 211102 (2018).
[5] T. Kurita, et al., Appl. Phys. Lett. 118 214001 (2021).

138Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β2-01
AC magnetic field sensing with ensemble NV centers
using electrical detection methods

Hiroki Morishita1, Naoya Morioka1, Tetsuri Nishikawa1, Hajime Yao1, Shinobu Onoda2,
Hiroshi Abe2, Takeshi Ohshima2, and Norikazu Mizuochi1
1Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.

2

National Institutes for Quantum and Radiological Science and Technology, Takasaki, Gunma, 370-1292, Japan.
h-mori@scl.kyoto-u.ac.jp

Introduction
Nitrogen-vacancy (NV) centers in diamond have a long coherence time at room temperature, and hence they are candidates
for quantum sensors and quantum information processing devices [1]. While electrical detection of NV spins is essential todevelop and integrate these quantum devices [2-8], to the best of our knowledge, there are no demonstrations of AC magnetic
field sensing using electrical detection methods. In the electrical detection of the NV spins, the change in the photocurrent ismeasured when resonant microwaves are applied to the NV spins. In the demonstration of the AC magnetic field sensing
using electrical detection methods, the current generated by the AC magnetic field flows in the diamond sample. This current
generated by the AC magnetic field can cause an increase in noise in the electrical detection method. Thus, the AC magnetic
field sensing using the electrical detection method is still challenging. In this study, we demonstrate for the first time AC
magnetic field sensing using the electrical detection method by reducing the influence of such a current.

Method & Results

AC Signal (arb. units)

In this study, we performed the AC magnetic field sensing with an electrical detection method using the ensemble of NV
centers (concentration of ~ 1.4 ×1017 cm-3) created by electron-beam irradiation followed by annealing. Figure 1 shows aresult of AC magnetic field sensing with the electrical detection method with the bias voltage of 5 V. The result indicatesthat we observe ~ 3 × 10-8 T/√Hz of the sensitivity of the AC magnetic field. In this presentation, we discuss the results of
AC magnetic field sensing using the electrical detection method.

0

2

4

6

8

Magnetic Field (µT)

10

Fig.1 AC magnetic field sensing with an electrical detection method.

Acknowledgments

We thank T. Ono and T. Moriyama for their technical help. This work was supported by MEXT Q-LEAP (No.
JPMXS0118067395), KAKENHI (No. 15H05868，No. 19H02546), and Kyoto University Nano Hub.

References

E. D. Herbschleb et al., Nat. Commun. 10, 3766 (2019).
E. Bourgeois et al., Nat. Commun. 6, 8577 (2015).
3
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
H. Morishita et al., Sci. Rep. 10, 792 (2020).
7
T. Murooka et al., App. Phys. Lett. 118, 253502 (2021).
8
M. Gulka et al., Nat. Commun, 12, 4421 (2021).
1
2

139

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β2-02
OPuS-MAGNM - Miniaturized Optically Pumped Solid State Quantum
Magnetometers for Space Applications
Hannes Kraus1, Corey J. Cochrane1
1

NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
hannes.kraus@jpl.nasa.gov

The OPuS-MAGNM project proposes to develop a novel low-cost low-power rad-hard miniaturized solid-statemagnetometer for planetary magnetic field sensing. This technology leverages optically active, spin-carrying quantum
centers (QC) in wide-bandgap semiconductors such as diamond or silicon carbide. External magnetic fields cause changes
in the QC spin energy conformation, which can be detected optically. Wide-bandgap solid-state systems, in comparison togas-cell based optically pumped magnetometers are interesting because of the material’s intrinsic extensive temperature
range (QC deterioration starts above Venus surface temperatures, at about 700C), and radiation hardness (QC implantation
fluence ~1017 e/cm2 vs. Europa orbit 30 day fluence ~1013 e/cm2). Additionally, the sensor lends itself to miniaturization, as
QC are sensitive down to single emitters, i.e. small, sub-mm ensembles are sufficient sensor volumes.
The U.S. Planetary Science Decadal Survey identifies the need for a number of scientific instruments addressing the threecrosscutting themes of planetary science: (1) understanding solar system beginnings, (2) searching for the requirements forlife and (3) revealing planetary processes. Magnetometers are unassuming, but powerful tools aiding in all of these themes.
The proposed technology is an extension to the recent Silicon Carbide solid-state magnetometer (SiCMAG1), adding
substantially better sensitivities at the expense of requiring optical readout2. We leverage optical readout noise being shotnoise in nature, while all-electrical systems suffer from 1/f noise. This gives the optical readout approach a significant
advantage in low-frequency and long-term stability performance metrics.
Consider the two most commonly used magnetometer technologies flown in space: Fluxgate systems exhibit highsensitivities and all- electrical simplicity, but require multiple coils per spatial direction. Additionally, fluxgates are not selfcalibrating; drifts in absolute field values necessitate either augmenting the fluxgate system with a self-calibrating system orincorporating complicated spacecraft roll maneuvers into mission planning.
Optically pumped He cell systems can counter this issue, operating both in scalar and vector mode, also with very highsensitivities. Their downside is the added complexity of the gas cell, with Helium being notoriously prone to outgas. Also,
vector-helium systems are larger and more expensive than fluxgates. OPuS-MAGNM now marries the solid-state simplicity
of fluxgates and SiCMAG with the precision and self-calibration capabilities of an atomic gas magnetometer system, withimproving longevity over gas cells. It has the potential to provide self-calibrated, heritage-level vector magnetic field sciencein a radiation-hard and thermal/vacuum-rugged miniaturized package; well suited for all kinds of planetary science missions.
FIG. 1. Illustration of the signal genesis of the
optically detected magnetic resonance(ODMR) in wide-bandgap solid-state
semiconductors. Silicon vacancies in Silicon
Carbide (h,k)
are optically. active spincarrying quantum centers, addressable byresonant excitation of electronic and radio
frequency transitions. An exemplary ODMR
spectrum at zero magnetic field and 1mT field
ist shown at the bottom left. A calculation of
the resonance positions depending on themagnetic field is shown on the bottom right.3

References
1. C.J. Cochrane, J. Blacksberg, M.A. Anders, P.M.
Lenahan. Vectorized magnetometer for space
applications using electrical readout of atomic scale
defects in silicon carbide. Sci. Rep. 2016, 6 (1), 1239.
2. H. Zheng, J. Xu, G.Z. Iwata, et al. Zero-Field
Magnetometry Based on Nitrogen-Vacancy Ensembles
in Diamond. Phys. Rev. Applied 2019, 11 (6), 064068.
3. H. Kraus, V.A. Soltamov, F. Fuchs, et al. Magnetic
field and temperature sensing with atomic-scale spin
defects in silicon carbide. Sci. Rep. 2014, 4, 5303.

140

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β2-03
Development of phthalocyanine ion beam for creation of multiple NV centers
Kosuke Kimura1,2, Shinobu Onoda1, Keisuke yamada1, Wataru Kada2, Tokuyuki Teraji3,
Junichi Isoya4, Osamu Hanaizumi2, and Takeshi Ohshima112National Institutes for Quantum Science and Technology

Graduate School of Science and Technology, Gunma University
3
4

National Institute for Materials Science

Faculty of Pure and Applied Sciences, University of Tsukuba
t201d208@gunma-u.ac.jp, kimura.kosuke@qst.go.jp

Introduction
A nitrogen vacancy (NV center in diamond is known as a solid-state spin qubit worked at room temperature. NV centerscoherently coupled by dipole-dipole interactions have a potential to accomplish quantum registers operatable at room
temperature. Since the dipole-dipole interaction is inversely proportional to the cube of the distance between the NV centers,
it is necessary to create NV centers in close proximity to each other. One of the methods to create NV centers in close
proximity is nitrogen (N ion implantation via a nanohole mask [1]. This method has been reported to create double coupled
NV centers. However, for reason of nanohole purification technology, it has been difficult to create multiple coupled NV
centers with this method. The other method is molecular ion implantation [2,3]. In 2013, Yamamoto et al. reported the dipolar
coupled NV center pair via nitrogen molecular ion (N2+ implantation [2]. In 2019, Haruyama et al. reported the implantationof molecular ion from an adenine (C5N5H5 ion source and demonstrated to create triple coupled NV centers [3]. It is expected
to create further multiple coupled NV center by implantation of molecular ion with a higher number of nitrogen atoms than
C5N5H5. In this study, we report to develop a phthalocyanine(C32N8H18 ion beam containing eight nitrogen atoms forcreation of multiple NV centers.

Method and result

The C32N8H18 ion beam was developed using an ion implanter. Firstly, C32N8H18 powder was vaporized and ionized by aheater at 336°C in the support gas (Ar ambient. Secondly, positive ions were electrically extracted by energy of 3 keV.
Thirdly, the extracted beam was analyzed by mass spectrometry. The result of mass spectra was showed FIG. 1. The
fragments, such as C6H4, C8H4, C8N2H5, etc., and Ar were detected in mass number ranging from 0 to 250. C32N8H18 ion was
detected around the mass number of 505. finally, the C32N8H18 ion beam extracted by mass spectrometry magnet was
accelerated at the energy of 281 keV and implanted into the sample.
The NV centers created by C32N8H18 ion implantation were observed
Ar
C H
using confocal fluorescence microscopy (CFM). The measurement of
C N H
photon counts and optically detected magnetic resonance (ODMR)
were performed with 532 nm laser and microwaves. FIG. 2(a) shows atypical image observed by a CFM with area of 20×20 μm2. Isolated
C32N8H18
spots are clearly found from C32N8H18 implanted region. FIG. 2(b)shows the ODMR spectra of the spot indicated by the circles andpentagon in FIG. 2(a). It is clear from the spectra that the spots labeled
NVA, NVB, NVC, and NVD contain a single NV center with different
axes. The spectrum labeled NVABCD is the result of the ODMR
FIG. 1. Mass spectra from the C32N8H18 ion
measurement of the spot indicated by the pentagon symbol in FIG.
source.
1(a). from the number of dips in this spectrum, the creation of four NV(a)(b)
centers with different orientation axes was observed per spot.
NV
5 µm
Therefore, we succeeded to create four NV centers in a spot by
NV
C32N8H18 ion implantation. In the presentation, I will report on theNVNVNV
probability of the creation of multiple NV centers.
NV
8

4

8

2

5

A

B

C

ABCD

Reference[1] I. Jakobi, et al., J. Phys., 752, 012001 (2016).
[2] T. Yamamoto, et al., Phys. Rev. B, 88, 201201 (2014).
[3] M. Haruyama, et al., Nat. Commun., 10, 2664 (2019).

Acknowledgement

This work was supported by MEXT Q-LEAP Grant Number
JPMXS0118067395 and JST Moonshot R&D Grant Number
JPMJMS2062.

NVA

NVD

C

D

NVABCD

NVB

FIG. 2. (a) Typical CFM image (20×20 μm2).
(b) The ODMR spectra of the single NV
centers and quadruple NV center.

141

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β2-04
Fabrication of diamond protective film using microwave plasma CVD
towards high-quality quantum emitters
K. Hirokawa1, K. Fukuda1, P. Wang1, T. Taniguchi2, M. Hatano1 and T. Iwasaki1
1

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2International Center for Materials Nanoarchitectonics, National Institute for Materials Science,
hirokawa.k.ab@m.titech.ac.jp

Introduction
Quantum networks are expected to realize secure communication by using the transfer of quantum states. Quantum
emitters which can generate a quantum entanglement state are necessary to construct quantum networks. Group-IV color
centers in diamond has attracted due to the sharp zero photon line (ZPL) and resistance to external electric noise. Among thegroup-IV color centers, SnV and PbV are expected to have a long spin coherence time in the milli-seconds at Kelvintemperatures [1,2]. However, the fabrication process includes high-temperature anneal at 2100℃, resulting in deteriorationof the sample surface, which frequently etches the incorporated color centers and hinders the fabrication of nanophotonic
structures. To overcome this issue, in this study, diamond films were deposited on a diamond substrate containing SnV
centers to protect during the high- temperature anneal.

Method and Results

Figure 1 illustrates the fabrication process. We used a IIa-type diamond substrate (Element Six). Sn ions were implanted
into the substrate with an acceleration energy of 700 keV and a dose of 2×109/cm2. Then, diamond films were deposited by
two microwave plasma CVD systems for 40 hours in total. At the first growth stage, diamond films with low impurity
concentrations were synthesized at the low growth rate. Then, at the next stage, thicker diamond films were grown using ahigh-power plasma CVD system. This sample was treated at 2100℃ under 7.7 GPa to form SnV centers in the IIa-type
diamond substrate. Confocal fluorescence microscope observations were carried out at a cryogenic temperature.
The CVD film remained on the substrate after anneal at 2100℃. Figure 2 shows ZPL from the SnV centers after thehigh-temperature anneal. The two lines correspond to C- and D-peaks, originating from split energy levels of the SnV centers.
These observations indicate that the deposited diamond films worked as a protective layer to form SnV centers.

FIG.1. Schematic diagram of protective film
fabrication for the SnV center formation.

FIG.2. PL spectrum of SnV

Reference

T.iwasaki et al, Phys. Rev. Lett, 119, 253601 (2017)
P.Wang et al, ACS photonics,2947,2954(2021)

1
2

Acknowledgments

This work was supported by the Toray Science Foundation, the MEXT Quantum Leap Flagship Program (MEXT QLEAP) Grant No. JPMXS0118067395 and "Nanotechnology Platform Program" of the Ministry of Education, Culture,
Sports, Science and Technology (MEXT), Japan, Grant Number JPMXP09F-21-IT-013.

142

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β2-05
A compact quantum sensor head with side excitation of CVD diamond
Yuki Nishio1, Yuji Hatano1, Jaewon Shin2, Daisuke Nishitani1, Ryo Matsuki1, Hiromitsu Kato3, Shinobu Onoda4,
Takeshi Oshima4, Keigo Arai1, Mutsuko Hatano1, and Takayuki Iwasaki1
1

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
2

Yazaki Corporation

3

National Institute of Advanced Industrial Science and Technology
4National Institutes for Quantum Science and Technology
nishio.y.ac@m.titech.ac.jp

Introduction
A compact sensor system is important for practical applications of quantum diamond sensors using NV centers. There
have been reports on nanotesla to sub-nanotesla sensitivities for the small modular diamond sensor, such as 3 nT⁄√Hz byside excitation on a (100 crystal1, 310 pT⁄√Hz by perpendicular excitation on a (100 crystal2, and 344 pT⁄√Hz byperpendicular excitation on a (111 crystal3. In this report, we investigate the side excitation of a CVD diamond layer on a(111 crystal including a large volume of NV centers.

MethodThe configuration of the sensor head fabricated in this experiment is shown in FIG.1. A 110 μm-thick 12C-enriched CVD
film grow n on 2.0✕ 2.0✕ 0.3 mm3 IIa (111)substrate was used as the diamond sensor. The NV centers were formed by
5.0✕1017 cm -2EB irradiation and high-temperature anneal. The excitation green laser was introduced on a sidewall of the
CVD film, and the fluorescence emitted from the NV centers was then collected by a CPC lens and led into a photodiodethrough LPFs. The microwave antenna was made of copper tape and the microwave magnetic field was applied horizontally.
The antenna was placed on an AlN heatsink plate. In order to excite only the NV-rich region in the diamond sample, thelaser diameter was adjusted using a beam expander and focusing lens. A part of the excitation laser was extracted as areference light to cancel the laser noise from the fluorescence. The optical system was placed in a 1 mm-thick permalloy
single layer magnetic shielded box.

ResultFirst, we investigated the magnetically insensitive noise and slope of the lock-in ODMR by varying the deviation
frequency (Fig. 2a. Although the slope takes the maximum value at a deviation frequency of 500 kHz, in this experiment,
we set the deviation frequency around 350 kHz, where the noise/slope becomes small. The measured magnetic field noise
spectrum is shown in Fig. 2b. The sensitivity was estimated to be 770 pT⁄√Hz and the noise floor was 400 pT⁄√Hz
between 30-100 Hz. In this frequency range, the noise floor of magnetically sensitive is comparable to that of themagnetically insensitive. The shot-noise limit sensitivity, calculated from the contrast and linewidth measured from theODMR, is 15 pT⁄√Hz, expecting a higher magnetic field sensitivity by improving the measurement system. This work was
supported by MEXT Q-LEAP Grant Number JPMXS0118067395.

Reference

J. Webb et al., Appl. Phys. Lett. 114, 231103 (2019)
F. Stürner et al., Adv. Quantum Technol. 4, 2000111 (2021)

1
3

R. Patel et al., Phys. Rev. Appl. 14, 044058 (2020)

2(a)Optical filter
Diamond532nm laser

Antenna
AlN
1 cm

FIG.1 Sensor module for sidelaser excitation.

10

6

8

5

6

4
3

4

2

noise/slope

1

slope

0

200

300
400
500
600
Deviation frequency [kHz](b)slope [V/MHz]

Photodetector
CPC lensnoise/slope [kHz]

7

2
700

0

FIG.2 (a) Ratio of the magnetically insensitive noise to the slope of the lock-in
ODMR and the slope depending on the deviation frequency. (b) Measured FFTspectrum of sensitivity. The black dotted line indicates 400 pT⁄√Hz.
143

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-β2-06
Hybrid integration of Si3N4 grating structure on diamond NV substrate for
efficient photon extraction
Ryota Katsumi1, 2, Takeshi Hizawa1, Akihiro Kuwahata2, 3, Takayuki Iwasaki 4, Mutsuko Hatano 4,
Fedor Jelezko5, Masaki Sekino2, and Takashi Yatsui1, 2
1

Graduate School of Engineering, Toyohashi University of Technology
Graduate School of Engineering, The University of Tokyo

2

Graduate School of Engineering, Tohoku University

3
4

School of Engineering, Tokyo Institute of Technology
Institute of Quantum Optics, Ulm University

5

katsumi.ryota.ti@tut.jp

Introduction
Nitrogen-vacancy (NV) centers in diamond is a promising candidate for a quantum sensor, especially a sensitive
magnetometer thanks to their excellent spin property1,2. However, their demonstrated magnetic field sensitivity is far beyond
those based on superconducting quantum-interference devices. One of the critical issues is the low extraction efficiency ofthe emitted photons from the diamond NV substrate3. This can be overcome by implementing the nanostructure on diamondincluding gratings, but the fabrication of such structure on diamond is technically difficult.

MethodIn this work, we demonstrate the hybrid integration of grating structure on a diamond NV substrate using transfer printing,which is based on a simple pick-and-place operation4. Figure 1(a) displays the SEM image of the grating based on Si3N4,
which is transparent for the NV emission wavelength of around 700 nm. To pick them up, we employed the air-bridged
structure for the grating. By using the transfer printing [Fig. 1(b)], the Si3N4 grating was integrated on the diamond NV
substrate. Figure 1(c) displays the optical microscope image of the fabricated device. The grating is indeed bonded with the
diamond NV substrate. The detailed design and characterization will be discussed in the presentation.

FIG. 1. (a) SEM image of the fabricated Si3N4 grating. (b) Schematics of the transfer printing-based integration of Si3N4
grating on diamond. (c) Optical microscope image of the fabricated device.
Acknowledgement
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067395 and Kakenhi (18H01470, 20H02197,
20H05091, 20K21118).
References
1

J. M. Taylor, et al., Nat. Phys. 4, 810 (2008).

2

A. Kuwahata, et al., Sci Rep 10, 2483 (2020).

3

D. Le Sage, et al., Physical Review B 85, 121202 (2012).

4

R. Katsumi, et al., Optica 5, 691 (2018).

144

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-γ2-01
Superconducting nanostrip single-photon detectors with dielectric multilayer
cavities
Fumihiro China1, Shigehito Miki1,2, Satoru Mima1, Masahiro Yabuno1, Shigeyuki Miyajima1 and
Hirotaka Terai11Advanced ICR Research Institute, National Institute of Information and Communications Technology
2

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

Introduction
Superconducting nanostrip single-photon detectors (SNSPDs) have attractive features such as high detection efficiency,
low dark count rate, and low timing jitter, and are promising instruments in various fields, including quantum information
science [1]. The superconducting nanostrip consisting of a thin and narrow meandering line potentially has photon sensitivity
in a wide wavelength range from ultraviolet to mid-infrared, but the optical absorptance of only a single nanostrip layer is as
low as few tens of percent. The SNSPDs integrated with dielectric multilayer (DML) cavities, as shown in FIG. 1, areeffective structures to enhance the optical absorptance of the nanostrips at the target wavelengths. The DMLs are composedof two dielectric materials with different refractive indexes. By optimizing the layer structure such as the number of layers
and film thickness of each layer, the optical properties of SNSPDs can be designed flexibly according to the requirement [2].
In this presentation, we show the development of SNSPDs with DMLs for various wavelength regions.

MethodWe have designed and developed SNSPDs with DMLs using SiO2 and TiO2 for the visible wavelength, SiO2 and Si forthe telecom wavelength, and Ta2O5 and Si for the mid-infrared region, respectively. FIG. 1 shows a schematic of an SNSPD
with a DML composed of SiO2 and TiO2, which is designed for 780 nm wavelength region. First, the layer structure of the
DML was optimized for the target wavelength using a thin film calculation software. Subsequently, we simulated theabsorptance dependence on the polarization state of incident photons by finite-element analysis. As results, the optimized
number of layers and the total thickness of the DML are 17 layers and 2.02 µm, respectively. Since it was also confirmedthat the optical absorptance of the nanostrip depends on the polarization state of the incident photon, SiO film is depositedon the nanostrip to minimize the polarization sensitivity at the wavelength of 780 nm. Then, we fabricated the nanostrip
devices according to the optimized design of SNSPD with the DML and evaluated the wavelength dependence of the system
detection efficiency (DE) using a supercontinuum light source. FIG. 2 shows the wavelength dependence of the opticalabsorptance and measured system DE. The obtained dependence of the system DE well agrees with optical absorptancedependence in the simulations, and we obtained a high system DE of 85% at 780 nm. The developments of SNSPDs forother wavelengths will be talked in the presentation.

Acknowledgment

This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067634, JST CREST Grant Number
JPMJCR1671, and JST Moonshot R&D Grant Number JPMJMS2066.

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. Schematic of the device structure of an SNSPD
with a DML. The number of layers and total thicknessof the DML are 17 layers and 2.02 µm, respectively.

FIG. 2. Comparison of the simulated opticalabsorptance of the NbTiN nanostrip and the measured
system DEs.

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SE-03A-γ2-02
Estimation of the quantum efficiency of the up-conversion system based on
injection-locked dual oscillators
Masayuki Hojo1, Shuntaro Tani2, Yohei Kobayashi2, and Koichiro Tanaka1
1

Department of Physics, School of Science, Kyoto University
2

ISSP, The University of Tokyo

hojo.masayuki.33e@st.kyoto-u.ac.jp
Introduction
Spontaneous parametric down-conversion (SPDC) is essential tool for a quantum light source in the infrared region
ranging 2-5 µm for the purpose of material identification, chemical analysis, and gas sensing. However, SPDC process
has a technical limitation of low efficiency and can be detected only by sensitive detectors. Up-conversion detecting
system has been demonstrated to bridge such a gap. So far, existing technique1 has been concentrated into the conversion
efficiency, in which the temporal duration of the light source was highly broad. In this work, we implement the upconversion detector using two Er- and Yb-doped fiber lasers (EDFL and YDFL) with the duration narrower than theconventional one.

MethodFigure 1 illustrates the schematics of the up-conversion system. The EDFL output at 1.56 µm was split into two ports,
which served as the injecting seed and the pump for down frequency generation (DFG) process in PPSLT, respectively.
The repetitions of EDFL and YDFL was synchronized at 57.9 MHz. The YDFL output had the spectral shape narrowed
by Fiber-Bragg-Grating (FBG) and was boosted to 100mW. Similarly, the amplified pulse was divided into two portions,the DFG port and the up-conversion port. In the DFG port, the two pulses at 1.03 and 1.56 μm were spatially combinedwith a wavelength division multiplexer (WDM) and produced a MIR pulse by DFG process. The MIR light source wasthen introduced into PPLN crystal. The pump for the up-conversion was focused into PPLN in the collinear configuration
with the MIR pulse. The SFG signal in the visible region was detected by a sensitive detector.
In our presentation, we will report the result of up-conversion detection and discuss about the system improvement.

Fig. 1 Schematics of the whole system.

Acknowledgement

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

Reference
1.

Huang, K. et al. Photonics Res. 9, 259 (2021).

146Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03A-γ2-03
Selective measurement of biexciton luminescence by photon correlation
spectroscopy
Hiroya Seki1, Keita Hashimoto2, Jun Ishihara2, Kensuke Miyajima2, Ryosuke Shimizu1
1

Department of Engineering Science, The University of Electro-Communications
2

Department of Applied Physics, Tokyo University of sciences2043006@edu.cc.uec.ac.jp

Introduction
Coincidence measurement performed by two detectors is a common technique to detect photon pairs in quantum opticalexperiments [1] and allows us to extract two-photon events from the input state of light [2]. This technique has been used indemonstrating fundamental concepts of quantum mechanics, quantum information protocols, and quantum imaging. On theother hand, we also expect the application of coincidence measurement to spectroscopy as a new development of quantum
technology. Combining the coincidence counting with frequency-resolved measurement could bring us a new approach tospectroscopy in a quantum manner. Hereafter we refer to it as photon correlation spectroscopy (PCS) [3]. The Photonnumber-resolving ability of PCS may provide a powerful tool to analyze a complex quantum system in condensed matter.
Here we present a proof-of-concept experiment of PCS with biexciton luminescence.

MethodBiexciton is generated via a two-photon resonant excitation by the second harmonic of a mode-locked Ti: sapphire laser, andthen decays into two polaritons; a higher energy polariton (HEP) and a lower energy polariton (LEP). After propagating in
the crystal, the polaritons are converted into photons at the crystal surface. In this process, the sum of the two-photon energy
should be the same as biexciton energy due to the phase-matching condition. We employed a femtosecond laser with the
bandwidth of 4.4 nm, corresponding energy width of 9.0 eV, to clarify the photon-number-resolving ability. In this situation,
the spectrum of Rayleigh scattering light of the laser overlaps that of biexciton luminescence. Therefore, it is difficult todistinguish the biexciton luminescence from the laser spectrum. In contrast, PCS enables us to observe HEP and LEP due tothe photon-number-resolving ability.
In order to characterize two-photon spectral
distributions, joint spectral intensity (JSI) plotted in a
two-dimensional space has been employed in thequantum optics field [4]. The JSI represents the twophoton probability distribution as a function of theenergy of the constituent photon. Experimentally, werecorded the coincidence counting values by scanning
the transmission frequency of two monochromaters for
the JSI measurement.
Figure 1 shows the measured JSI of biexciton
luminescence. We can see a single peak distribution
caused by coincidence counts of HEP and LEP. We
estimated the spectral width of HEP (LEP) as 0.94 (1.2)
meV from the projection of the JSI onto the vertical(horizontal) axis, which is narrower than the bandwidthof the laser. This result implies a successful
demonstration of PCS.
FIG. 1. JSI of biexciton luminescence.

Acknowledgment

This work was supported by MEXT Q-LEAP Grant Number JPMXS0118069242.

Reference

C. K. Hong, Z. Y. Ou, and L. Mandel, Phys. Rev. Lett., 59, 2044-2046 (1987).
H. Seki, K. Miyajima, R. Shimizu, arXiv:2109.03715 (2021)
3
C. M. Muñoz, and F. Schlawin, Phys. Rev. Lett., 124, 203601 (2020).
4
P. G. Evans, R. S. Bennink, W. P. Grice, and T. S. Humble, Phys. Rev. Lett., 105, 25361 (2010).
1
2

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SE-03A-γ2-04
Towards Optical Manipulation of Gold-Nanoparticles for Efficient Single
Photon Sources
Rui Sun1, Yining Xuan1, Soyoung Baek1, and Keiichi Edamatsu1
1Research Institute of Electrical Communication, Tohoku University
sun@quantum.riec.tohoku.ac.jp

Quantum dot is a promising candidate for constructing a single photon source because of its broad and continuous
excitation spectrum, adjustable wavelength, high photochemical stability, and long fluorescence lifetime1. Our research
focuses on the single photon source based on quantum-dot-gold-nanoparticle coupled system on optical nanofiber2.
Combining with the Purcell effect3, the rise time of the second order intensity correlation function for quantum dot can beenhanced. However, the position of gold-nanosphere on nanofiber is entirely random, which makes the quantitative study ofsingle-photon emission rate difficult. We propose a non-contact method to control the position of a gold-nanoparticle on thenanofiber making use of an optical tweezer. We calculate the optical responses and heating effects of a gold-nanoparticle
trapped in optical tweezer to define the optimal wavelength and laser power for the experiment.
The optical response of a gold-nanoparticle submerged in water and trapped in an optical tweezer is calculated based on
Mie theory. Figure 1 is the scattering and absorption efficiencies of a gold-nanoparticle in an optical tweezer. The red andblue curves are the scattering (Qsca)and absorption (Qabs)factors, respectively. The abscissa is the size parameter (𝑘𝑘𝑘𝑘)of thegold-nanoparticle; 𝑘𝑘 is the wave number of the light and 𝑘𝑘 is the radius of gold-nanosphere. Here, the gold-nanoparticle
size ranges from 0 to 200 nm. For the same particle size, the longer the optical wavelength is, the weaker the effect ofabsorption and scattering.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067581.

FIG. 1. Scattering and absorbing efficiencies of gold-nanoparticle trapped in optical tweezer.

References
O. Gazzano and G. Solomon, J. Opt. Soc. Am. B, 33, C160-C175 (2016).
M. Sadgrove, M. Sugawara, Y. Mitsumori and K. Edamatsu, Sci Rep, 7, 17085 (2017).
3
Q.Gu, and Y. Fainman, Semiconductor Nanolasers, (pp. 65-90) (2017).
1
2

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SE-03A-γ2-05
Single photon emission from a quantum-dot-gold-nanostar coupled system on an
optical nanofiber
Yining Xuan1, Masakazu Sugawara1, Rui Sun1, Soyoung Baek1, Keiichi Edamatsu1, and Mark
Sadgrove2
1

Research Institute of Electrical Communication, Tohoku University

2

Department of Physics, Faculty of Science, Tokyo University of Sciencexuan@quantum.riec.tohoku.ac.jp

Single-photon emitters play an important role in many leading quantum technologies such as quantum communications
and quantum cryptography. Therefore, coupling them to existing fiber network can be a promising candidate for the various
applications in quantum network. As a carrier of photon transportation, optical nanofiber has the advantage of ultra-low loss,
low cost and high coupling efficiency [1]. Since the nanofiber has a diameter of hundreds of nanometers, photons emitted
from single photon emitters can be coupled into nanofiber through the evanescent field directly. Therefore, single-photon
source’s effective incorporation into nanofibers shows great potential in the construction of fiber-based quantum information
network. In 2012, Yalla et al. demonstrated the coupling of single photons from quantum dots into the nanofiber [2]. After
that, Liebermeister et al. succeed in coupling single photons from color centers in a diamond into the nanofiber [3].
Nevertheless, how much we can improve the coupling between the single-photon emitters and the nanofiber is still an open
question that needs to be addressed. In this research, in order to achieve Purcell-enhanced single-photon emission from aquantum dot (QD, we place gold nanoparticles, especially gold nanostars (GNS, in the vicinity of the quantum dot locatedon the surface of an optical nanofiber. By measuring the rise time of the second order correlation function 𝑔(2) (𝜏) for boththe GNS-QD system and the sole QD system, Purcell-enhancement can be verified.
We fabricate a nanofiber with the diameter of 474 nm by heating-stretch method [4][5], and place a GNS and a QD on thesurface of a nanofiber. Figure 1 shows scanning electron microscope (SEM image of GNS-QD coupled system. By scanninga laser beam spot along the nanofiber axis and measuring the photoluminescence (PL signal from the QD and the scattered
light from the GNS, we confirm the GNS and the QD is located within 1.5 𝜇m interval. Next, we measure second ordercorrelation function 𝑔(2) (𝜏) for both the GNS-QD system and the sole QD system on the same nanofiber. See Figure 2. The
obtained 𝑔(2) (0) for the GNS-QD and Sole QD was less than 0.5, a signature of anti-bunched single photons. The rise timeof 𝑔(2) (𝜏) for the GNS-QD and the SQD are obtained to be 167 ns and 107 ns, respectively; the GNS-QD exhibited ∼36 %reduction of the rise time in comparison to the SQD. Although it is likely to originate from Purcell enhancement, moredetailed and complete measurement and analysis are necessary to conclude.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0118067581.

FIG. 1. SEM image of GNS-QD coupled system.

FIG. 2. 𝑔(2) (𝜏) measurement of GNS-QD coupledsystem and sole QD system, respectively.

Reference

M. Sadgrove, M. Sugawara, Y. Mitsumori, and K. Edamatsu, Sci. Rep., 7, 17085 (2017).
R. Yalla, K. Nayak, and K. Hakuta, Opt. Express, Vol. 20, Issue 3, 2932 (2012).
3
L. Liebermeister et al., Appl. Phys. Lett., 104, 031101 (2014).
4
M. Sugawara, Y. Mitsumori, K. Edamatsu, and M. Sadgrove, Opt. Express, 28, 18938 (2020).
5
M. Sadgrove, T. Yoshino, M. Sugawara, Y. Mitsumori, and K. Edamatsu, Phys. Rev. Applied, 16, 044034 (2021).
1
2

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SE-03A-γ2-06
Focusing constraints on coupling efficiency of collinear type-I degenerated
SPDC photon pairs into a single-mode fiber
Nicolas Schwaller1,2, Geobae Park1, Ryo Okamoto1,3, and Shigeki Takeuchi1
1

Department of Electronic Science and Engineering, Kyoto University

2

Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
3

Japan Science and Technology Agency, PRESTO
schwaller.nicolas.52z@st.kyoto-u.ac.jp

Introduction
Entangled photon pairs represent an essential resource for various quantum technologies, such as quantum key distribution,
quantum computing or quantum imaging. A common process to produce correlated pairs is spontaneous parametricdownconversion (SPDC) of pump photons into pairs of entangled photons which are then coupled into a single-mode (SM)fiber. For most applications, it is desirable to maximize the coupling efficiency of the entangled pairs into the SM fiber, as
well as the rate of pairs that can be collected. Systematic studies about the maximization of these quantities have been carriedout for specific parameters of SPDC, e.g. using type-II phase-matching condition [1]. However, despite advances ontheoretical modelling [2,3], other SPDC configurations still lack experimental evidence to confirm the dependence of thecoupling efficiency on the main parameters of the setup. This study focuses on collinear degenerated co-polarized SPDC
photon pairs. They are relevant for various applications such as single mode squeezed states for gaussian boson sampling,
and non-linear interferometers.

MethodWe investigate the dependence of the correlated-mode coupling efficiency ηc on pump and collection beam waists bycontinuously varying their size thanks to two beam expanders (FIG. 1). We generate type-I SPDC by pumping a bulk beta
barium borate (BBO) crystal of L= 3 mm length with a continuous wave (CW) 404 nm laser. We measure the coupling
efficiency using coincident detections from single photon counting modules (SPCMs), and study the impact of different
focusing conditions of the pump and collection beam. The estimated coupling efficiency was obtained by considering thelosses of the optics and the experimentally determined quantum efficiencies of the SPCMs. The observed ηc reached up to98%.

FIG. 1: Experimental setup enabling to change the focus ofpump and collection beam in the crystal.
This work is supported in part by JST CREST Grant Number JPMJCR1674, Japan, MEXT Quantum
Leap Flagship Program (MEXT Q-LEAP) Grant Number JP-MXS0118067634, JST-PRESTO(JPMJPR15P4), and KAHENHI Grants-in-Aid No. 21H04444.

Reference

P. Ben Dixon et al., Phys. Rev. A, 90(4), 1-9 (2014).
R. S. Bennink, R. S., Phys. Rev. A, 81(5), 1–10 (2010).
3
H. E. Guilbert et al., IEEE Journal of Selected Topics in Quantum Electronics, 21(3), 215-224 (2015).
1
2

150

th
4 IFQMSThe 4th International Forumon Quantum Metrology and Sensing

PROCEEDINGS
Short Presentations by Young Researchers
Part 2: SE-03B

December 8th, 2021
Online Conference (Zoom)

Joint Program Session with Quantum Innovation 2021

151

.Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)
Quantum Sensing Track : Short Presentations by Young Researchers
SE-03B. Short Presentations by Young Researchers on SE-02, 05 Topics [4th 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)

Dec 8 (Wed.)
13:10-14:30

14:50-16:10

Session / Presentation

Mentor Chair Co-chair /Presenter

Affiliation

Abstract ID

SE-03B-01
MentorJohnjoe McFadden

U Surrey

MentorShigenori Tanaka

Kobe U

MentorKiminori Maeda

Saitama U

Chair

Noriaki Yahata

QST

Co-chair

Akinari Yokoya

QST

Intracellular thermal conductivity determined by dual-functionalized
diamond nanosensor

Madoka Suzuki

Osaka U

SE-03B-01-01

Label-free analysis of diffusion constant in lipid bilayers using nanoscalediamond magnetometry

Hitoshi Ishiwata

QST

SE-03B-01-02

Temperature sensing using silicon vacancy centers in detonation
nanodiamonds

Masanori Fujiwara

Kyoto U

SE-03B-01-03

Quantum-inspired machine learning for exponentially big neural data
analysis

Kei Majima

QST

SE-03B-01-04

Empirical verification of the violation of the temporal Bell inequality inbistable perception

Yasunori Aizawa

QST

SE-03B-01-05

Tracking radiation damage induction pathway following core-hole creationof DNA molecules in aqueous solution in aqueous solution

Yoshiaki Kumagai

TUAT

SE-03B-01-06

MentorPeter HoreU Oxford

MentorAkihito Ishizaki

IMS

MentorYasuteru Shigeta

U Tsukuba

Chair

Yoichi Takakusagi

QST

Co-chair

Tatsuhiko Imaoka

QST

High-resolution structure of an electron-transfer protein by neutron
crystallography

Yuya Hanazono

TMDU

SE-03B-02-01

Fabrication of a quantum sensor to reveal a topic in thermal physiology

Shuya Ishii

QST

SE-03B-02-02

Investigation of irradiation induced nitrogen-vacancy centers in 5nanometer-sized detonation nanodiamonds

Kit SoKyoto U

SE-03B-02-03

Formation of flavin anion and tyrosine radicals in avian Cryptochrome4

Hiroaki Otsuka

Waseda U

SE-03B-02-04

Do neural activities of binocular rivalry follow a quantum probability model?
Takahiro Hirao
A test of temporal Bell inequalities

QST

SE-03B-02-05

X-ray absorption spectroscopy of a silicon phthalocyanine derivative,
IR700, for X-ray excited photoimmunotherapy

Yudai Izumi

QST

SE-03B-02-06

Magnetically sensitive radical pairs in avian cryptochrome 4 proteins

Jingjing Xu

U Oldenburg

SE-03B-02-07

SE-03B-02

152

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-01-01

Intracellular thermal conductivity determined bydual-functionalized diamond nanosensor
Madoka Suzuki1
1Institute for Protein Research, Osaka University
suzu_mado@protein.osaka-u.ac.jp

Introduction
Cellular thermogenesis is an origin of rising body temperature. However, it is difficult to examine thermal effects in asmall scale such as a cell or a nanoparticle. The difficulty is caused by a simple reason; i.e., the thermogenesis occurs within
the volume of the heat source, while the heat escapes from its surface. When the size of a heat source (a fixed shape andvolume is considered) decreases by half, the volume of the heat source becomes 1/8, whereas the surface area decreases only
by 1/4. Therefore, as the scale of a system is reduced, the temperature rise can be orders of magnitude smaller and quicker
than in larger systems such as a tissue and an organism. This difficulty has been eased recently by a variety of temperaturenanoprobes and local heating methods. We can measure and manipulate temperature locally at the subcellular scale. Yet, theheat diffusion in cells, an essential knowledge to understand the results provided by those new methods, have never been
determined experimentally [1]. In many cases, the heat diffusion in a cell has been considered as similar to that in cells.

MethodHere, our recent study provided a new methodology to measure the thermal conductivity at the nanoscale [2]. The method
utilizes a dual-functionalized diamond nanosensor that functions as both a nanothermometer and a nanoheater. We foundthat the thermal conductivity in HeLa and MCF-7 cell lines is surprisingly smaller (about 1/6) than in water. This new findingthat the heat diffusion in a cell is significantly hindered than in water may suggest a new role of cellular thermogenesis in
biology beyond the conventional understanding of rising body temperature. Now we can expect that larger or longer heatpulses are formed by metabolic processes in cells [3]. Intracellular signaling is a biochemical reactions caused by a diffusionof molecules. We propose that "thermal" signaling could also be a part of this intracellular process.
This work was supported by JSPS KAKENHI Grant No. 19H03198 and by the Human Frontier Science Program No.
RGP0047/2018.

References

M. Suzuki and T. Plakhotnik, Biophysical Reviews, 12, 593–600 (2020). doi: 10.1007/s12551-020-00683-8
S. Sotoma, C. Zhong, J.C.Y. Kah, H. Yamashita, T. Plakhotnik, Y. Harada and M. Suzuki, Science Advances, 7, eabd7888(2021). doi: 10.1126/sciadv.abd7888
3
M. Suzuki and T. Plakhotnik, Applied Physics Letters, 119, 190502 (2021). doi: 10.1063/5.0063089
1
2

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SE-03B-01-02
Label-free analysis of diffusion constant in lipid bilayers
using nanoscale diamond magnetometry
Hitoshi Ishiwata1, Hiroshi C. Watanabe2, Shinya Hanashima3,
Takayuki Iwasaki4, Mutsuko Hatano4, Ryuji Igarashi1,51Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology
2

Quantum Computing Center, Keio University

3

Department of Chemistry, Graduate School of Science, Osaka University

4

Department of Electrical and Electronics Engineering, School of Engineering, Tokyo Institute of Technology
5

PRESTO, Japan Science and Technology Agency
ishiwata.hitoshi@qst.go.jp

Introduction
The NV center in a diamond is a quantum sensor with exceptional quality for highly sensitive nanoscale analysis of NMR
spectra. In this study, we investigate diffusion constant of a lipid bilayer, a biological parameter that determines the dynamics
of the lipid bilayer, utilizing ensemble-averaged nuclear spin detection from small volume ~ (6 nm)3, which was determinedby the depth of the NV center [1]. Observation of diffusion constant at different temperature reveals different phases of lipid
bilayer [2]. The result builds foundation for label-free imaging of cell membranes for observation of phase composition andpristine dynamics that determines cellular functions.

ResultIn Figure 1, the result of the correlation spectroscopy was compared with the 2D molecular diffusion model constructedby Monte Carlo simulation combined with results from molecular dynamics simulation. There is a change in diffusion
constant from 1.5 ± 0.25 nm2/μs to 3.0 ± 0.5 nm2/μs when the temperature changes from 26.5 °C to 36.0 °C. Observation ofdiffusion constant reveals different phases of lipid bilayer which identifies sub-compartment domains that are critical forcellular functions. In Figure 2, diffusion constant obtained from various different methods are shown. Previous results from
Fluorescence Recovery After Photobleaching (FRAP) vary significantly depending on the selected markers as shown in
Figure 2. Our results obtained from nanoscale diamond magnetometry are consistent with the results obtained from labelfree bulk measurement using Magic-Angle Spinning Pulse Field Gradient NMR (MAS PFG NMR). Our method builds
foundation for label-free imaging of cell membranes for observation of phase composition that determines cellular functions.

FIG. 1. Absolute value of correlation spectrum at
26.5 °C (1st and 2nd) and 36.0 °C are shown andcompared with results of 2D molecular diffusion

FIG. 2. Diffusion constant obtained from various measurement
method compared with nanoscale correlation spectroscopy

Reference:

H. Ishiwata, et al, APL, 111, 043103 (2017). 2H. Ishiwata, et al, Adv. Quantum Technol. 4, 2000106 (2021)
This research was supported by JST PRESTO Grant number JPMJPR17G1 and the MEXT Quantum Leap Flagship Program(MEXT Q-LEAP) Grant Number JPMXS0118067395, JPMXS0120330644.

1

154Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-01-03
Temperature sensing using silicon-vacancy centers in detonation nanodiamonds
Masanori Fujiwara1, Gaku Uchida1, Izuru Ohki1, Ming Liu2, Akihiko Tsurui2, Taro Yoshikawa2,
Masahiro Nishikawa2, and Norikazu Mizuochi1
1Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
Business Development Center, Daicel Corporation, 1239, Shinzaike, Aboshi-Ku, Himeji, Hyogo
671-1283, Japan
masafuji@scl.kyoto-u.ac.jp

2

Introduction
Nanodiamonds containing silicon-vacancy centers (SiV-NDs) are promising candidates for all-optical nanoscale
thermometry. For the practical application of SiV-NDs into a biological system like a living cell, NDs smaller than 30 nm
are suitable to pass through their membrane with minor damage. However, since the particle size of SiV-NDs reported
for temperature sensing is larger than 200 nm1, it is difficult to introduce such NDs into the target position without invasive
and complicated methods. As one of the efforts to overcome this problem, we developed SiV containing NDs via
detonation process (SiV-DNDs)2 since the detonation method can create small-size and massive NDs at a low cost. In thispresentation, we show the photoluminescence (PL) spectral response to the temperature of SiV-DNDs.
MethodWe first prepared polyglycerol-coated SiV-DNDs after purification and dispersion processes. The particle size of SiVDNDs is distributed at around 20 nm judging from the size histogram of 208 DNDs selected from a transmission electron
microscope (TEM) image as shown in Fig. 1(a). The particle size of the DNDs is small enough to use inside the cell. We
next prepared the SiV-DND suspension, dropped them on a coverslip, and dried them in ambient conditions. We observed
the PL image and spectrum by a homebuilt confocal microscope with a thermoplate to control the sample temperature.
From the confocal image, we found several bright spots (SiV-DND’s aggregations) with the SiV center’s zero phononline (ZPL) at a wavelength of 737 nm. Figure 1(b) shows ZPL peak wavelength (λp) as a function of the sample
temperature for a bright spot. We confirmed the λp linearly red-shifted with increasing temperature ranging from 22 ℃ to40.5 ℃. The peak wavelength sensitivity to temperature (Δλ/ΔT) is 0.015 nm K-1, which agrees with the result of SiV
center’s ensemble in a diamond substrate (0.0124 nm K-1)1. Using Δλ/ΔT, we evaluated the temperature sensitivity ηT,
which is defined the uncertainty σT at a unit measurement time tint (Fig. 1c). We found a bright spot with ηT = 1.1 K/√Hz,
which indicates sub-Kelvin precision was realized for 10 s integration time. All-optical thermometers such as small
nanoparticles will be a key factor for thermometry of nanosystems like organelle in the living cell.
This work was supported by MEXT Q-LEAP No. JPMXS0120330644.

Figure 1 (a) TEM image of SiV-DNDs. Scale bar indicates 100 nm. (b) ZPL peak wavelength (λp) as a function of thesample temperature for a bright spot (SiV-DNDs’ aggregation) selected from a confocal image. The peak sensitivity totemperature (Δλ/ΔT) was obtained by a line fit from the experimental data (filled circles). (b) Temperature uncertainty(σT) of the spot as a function of measurement time tint. The experimental data (filled circles) are fitted on a curve ∝1/�𝑡𝑡int .
Reference
1
C. T. Nguyen, et al., Appl. Phys. Lett., 112, 203102 (2018).
2
Y. Makino, et al., Diam. Relat. Mater., 112, 108248 (2021).

155Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-01-04
Quantum-inspired machine learningfor exponentially big neural data analysis
Kei Majima1,21Institute 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
Machine learning algorithms specialized for neural data have allowed the extraction of information encoded in the brain. As
an example, in previous studies, the images human subjects see were reconstructed from their brain activity measured via
functional magnetic resonance imaging (fMRI) [1]. However, the application of those machine learning algorithms to highresolution fMRI data, which may become mainstream in the near future, is limited due to their high computational cost. To
solve this problem, scalable machine learning algorithms are being designed by utilizing computational techniques developedin the field of quantum computation [2,3]. In this report, taking one of the popular statistical methods, principal component
analysis (PCA), as an example, we show that machine algorithms can be approximated with the use of such quantum-inspired
techniques. The computational time and approximation performance of quantum-inspired PCA are demonstrated. The main
results of this report have been presented in a previous paper by the author [3].

Methods

In this report, the computational time and performance were compared between quantum-inspired PCA and its exact
counterpart (i.e., exact PCA). Due to space limitations, the details of the algorithms and datasets used are omitted in thisreport; however, they have been explained in the previous study [3]. Briefly, the computational times of the two algorithms
were measured by applying them to simulation data. To characterize the dependence on the input dimensionality, the numberof input dimensions in the simulation data was systematically changed. The performances of those two algorithms were
evaluated by applying them to five benchmark datasets, and the variance explained by the top 100 PCs was measured andused as a performance metric in this report.

Results

Both the computational time and performance (i.e., explained variance) are shown in Figure 1. Results show that quantuminspired PCA was significantly faster than the exact PCA, and its performance was maximally 7% worse than the exact PCA
for these five datasets.

FIG 1. Comparison of the computational time and performance between quantuminspired PCA and its exact counterpart.

Discussion and Conclusions

In this report, quantum-inspired PCA was applied to simulation and real benchmark datasets, and its computational time andperformance were compared with those of the exact PCA. As results, quantum-inspired PCA was significantly faster thanits exact counterpart, and it showed moderate approximation performance on the five datasets. These results suggest apossibility that high-dimensional neural data whose size is intractable with previous machine learning algorithms can be
efficiently analyzed using such quantum-inspired algorithms.

References

G. Shen, T. Horikawa, K. Majima, Y. Kamitani, PLOS Computational Biology, Volume 15, e1006633 (2019).
E. Tang, Physical Review Letters, Volume 127, 060503 (2021).
3
N. Koide-Majima, K. Majima, Neural Networks, Volume 135, 55–67 (2021).
1
2This research was supported by MEXT Q-LEAP (JPMXS0120330644), JSPS KAKENHI (20K16465), JST ERATO(JPMJER1801), and JST PRESTO (JPMJPR2128).
156

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-01-05

Empirical verification of the violation of the temporal Bell inequality inbistable perception
Yasunori Aizawa1,2, Naotsugu Tsuchiya3, Emmanuel Pothos4, Jerome Busemeyer5, Peter Bruza6,
and Makiko Yamada1,71Institute for Quantum Life Science, National Institutes for Quantum Science and Technology
2
Graduate School of Medicine, Tohoku University
3
School of Psychological Sciences, Monash University
4
School of Arts and Social Sciences, Department of Psychology, City, University of London
5
Department of Psychological and Brain Sciences, Indiana University Bloomington
6
Faculty of Science and Technology, Queensland University of Technology
7
Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology
aizawa.yasunroi@qst.go.jp
Introduction

The purpose of the present study is to investigate quantum-like properties of mental states in bistable perception. In
order to do this, we tested whether the temporal Bell inequality applied to bistable perception experiments[1] can beviolated. In the present study, we used visual stimuli [2], where we can continuously and systematically manipulate two
types of ambiguities in the perceived rotation of dots. When the rotation angle is large, the stimuli induce bistable
percept. When the angle is small, the direction of rotation of the stimuli becomes difficult to judge. We use the stimuli
to test if the temporal Bell inequality can be violated, and if so, under what parameter regime, it can be violated.

MethodTwo patterns were presented alternately: a visual stimulus consisting of four disks, and one in which the disks wererotated by a specific angle (5-45 degrees) in each trial [FIG. 1(A)]. When the angle of rotation was close to 45 degrees,
stimuli were perceived to rotate in one of the two directions for a while with occasional reversals at random times (i.e.,bistable perception). When the angle of rotation was close to 5 degrees, no rotation was perceived beyond the angle ofrotation of the stimulus, and left and right rotations were perceived alternately, but the angle of rotation was so smallthat it was difficult to determine the direction of rotation [FIG. 1(B)]. At two time points after the beep, the participants
responded by pressing a button in the direction of rotation that they saw at that time [FIG. 1(C)].

FIG. 1. (A) Schematic illustration of the task. (B) A set of rotation angles (5-45 degrees in 5 degree steps). (C) Threetimings on the measurement of perceived stimuli. The perceived rotation direction was measured at two out of three
timepoints for the calculation of the temporal Bell inequality.

Reference

H. Atmanspacher, and T. Filk, J. Math. Psychol. 54, 314-321 (2010).
S. Takei and S. Nishida, J. Vision. 10, 23 (2010).
3
M. M. Wilde and A. Mizel, Found. Phys. 42, 256 (2012).
1
2

Acknowledgement

This work was supported by JSPS KAKENHI JP20H05711 and MEXT Q-LEAP Grant Number JPMXS0120330644.

157

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-01-06
Tracking radiation damage induction pathway following core-hole creation of
DNA molecules in aqueous solution
Yoshiaki Kumagai1,2, Masatoshi Ukai1,2, Akinari Yokoya3
1

Department of Applied Physics, Tokyo University of Agriculture and Technology
2

3Institute of Engineering, Tokyo University of Agriculture and Technology

Institute for Quantum Life Science, National Institute for Quantum Science and Technology
kumagai@go.tuat.ac.jp

Introduction
Ionizing radiation often causes irreversible DNA damage in a living cell of tissue and the mutation or cell death are thought
to arise from localization of damage known as a clustered DNA damage site[1]. Recently, it is recognized that the productionof the DNA molecules with inner-shell vacancies after irradiation can be a cause of clustered DNA damages [2]. We havereported the x-ray absorption near-edge structure (XANES) spectra at photon energies near the nitrogen K-shell ionization
potential of the base moieties of aqueous nucleotides [3]. The measuring excitation energies and binding energies of theelectrons in the nitrogen K-shell orbitals at different pH conditions predicted the hydration interaction of bases in nucleotides
with hydrated water molecules. This hydration interaction has been further confirmed by the spectroscopy of the secondary
and Auger electrons [4] (FIG.1). These findings gave rise to a possible deposition of excess charge from doubly ionized
DNA to water molecules, which may suppress the clustered DNA damage
induction. We studied the reaction pathways and dynamics of core-hole
DNA molecules in the aqueous solution with their identified electronic
states toward chemically stable and irreparable damages.
Results
We used monochromatic soft x-rays at SPring-8 BL23SU to selectively
excite or ionize an inner shell electron of a specific atom in aqueous
nucleotide molecules, which have been introduced into the vacuum using
a liquid micro-jet technique. In order to track the chemical reaction
sequences following initial core-hole states created by the primaryradiations, we have focused on particular events by excitation and to probe
outcoming luminescences [5]. This is a nondestructive analysis of theexcited intermediate species produced in a molecular reaction on thedamage induction pathway. We obtained the first evidence ofluminescence spectra of aqueous uridine-5’-monophosphate (UMP) after
x-ray absorption (FIG.2). The cause of luminescence can be due to theparent species produced following the double ionization of aqueous UMP,
and emission of excess positive charge and excess internal energy fromdouble charged UMP.
We also established the mass spectroscopy for the secondary ion
fragments produced via the relaxation of core-hole nucleotide molecules
in aqueous solution which extended the adaptabilities of the soft x-ray
spectrosopy for the DNA damaging using a liquid-jet technique.

FIG. 1. Electron kinetic energy spectra for
aqueous UMP at pH = 7.5 at the x-ray
photon energies of 480 eV and 490 eV [4].

Acknowledgement
This work was supported by JSPS KAKENHI (Grant Nos. 20H04338).
Reference
1
D. Goodhead, Int. J. Radiat. Bio., 65, 7 (1994).
2
A. Yokoya et al., in Charged Particle and Photon Interaction withMatter, (CRC Press: Boca Raton, 2011), pp.543-574.
3
H. Shimada et al., Chem. Phys. Lett., 591,137 (2014); H. Shimada et al.,J. Chem. Phys., 141, 055102 (2014); H. Shimada et al., J. Chem. Phys.,142, 175102 (2015).
4
Y. Takeda et al., Quantum Beam Sci., 4, 10 (2020)
5
Y. Terao et al., Int. J. Radiat. Bio., (published online; 2021)

FIG. 2. Yields of x-ray induced luminescence
for aqueous UMP and pure water as afunction of x-ray photon energy [5]. The inset
shows the XANES spectra for aqueous UMP.

158

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-02-01
High-resolution structure of an electron-transfer protein by neutron
crystallography
Yuya Hanazono1,2,3, Yu Hirano2,4, Kazuki Takeda1, Katsuhiro Kusaka5, Taro Tamada2, and Kunio
Miki1
1

Department of Chemistry, Graduate School of Science, Kyoto University

2

Institute for Quantum Life Science, National Institutes for Quantum Science and Technology
3

Medical research Institute, Tokyo Medical and Dental University
4

PRESTO, Japan Science and Technology Agency

5

Frontier Research Center for Applied Atomic Sciences, Ibaraki University
hanazono.str@tmd.ac.jp

Introduction
High-potential iron-sulfur protein (HiPIP) is a component of electron transfer from cytochrome bc1 complex to lightharvesting-reaction center complexes (LH1-RC) in bacterial photosynthesis. HiPIP possesses a cubane-like Fe4S4 cluster at
its center with a redox potential of above +300 mV. This high potential arises from the hydrogen bonds and hydrophobic
environment around the iron-sulfur cluster [1–3]. In order to clarify the effect of hydrogen bond on the redox potential andreaction mechanism, we determined the neutron structure of HiPIP and obtained the precise locations of the hydrogen nuclei.

Methods

We collected X-ray and neutron diffraction data of oxidized HiPIP at 0.66 and 1.2 Å resolution, respectively, from thesame crystal at a cryogenic temperature of 100 K. The initial refinement of X-ray data was performed at 1.2 Å resolution.
Then, the refinements with anisotropic atomic displacement parameters were performed at 0.66 Å resolution. After that, thejoint refinement of neutron and X-ray data was performed. The amide protons that had occupancies more than or equal to0.60 that of deuterium or 0.75 that of protium and the deuterium atoms of the side chains in a single conformation wererefined without geometry restraints.

Results

In the case of the NH…O hydrogen bond, most of the nucleus positions of the amide protons shift toward the acceptor
atoms. These hydrogen atoms are attracted by the electrostatic force. On the other hand, some hydrogen atoms point awayfrom the acceptor atoms. Around these hydrogen atoms, there is another oxygen atom nearby that can form a hydrogen bond.
Generally, the planarity of the peptide bond is discussed based on ω-angles due to the insufficient structural data for theamide protons. In this study, we focus on the planarity of the Hi-Ni-Ci-1=Oi-1 planes, where i represents the residue number,in the peptide bond. To evaluate the planarity of peptide bonds including hydrogen atoms, the positions of hydrogen atoms
and oxygen atoms are defined with the in-plane angle (γH, γO), the out-of-plane angle with the Ci-1-Ni-Cαi plane (δH, δO).
There is a substantial correlation between δH and δO. When the amide protons deviate from the peptide plane owing to theelectrostatic interaction, the position of the oxygen atoms of previous residues shifts in the opposite direction. Consequently,
the planarity of the Hi-Ni-Ci-1=Oi-1 planes is mainly preserved. Moreover, the orientation of the amide proton of Cys75 isdifferent in the reduced and oxidized states possibly due to the electron storage capacity of the iron-sulfur cluster. The change
in the electron storage capacity will facilitate the electron transfer from HiPIP to LH1-RC.

References

T. Glaser et al., Schmitt, J. Am. Chem. Soc., 123, 4859–4860 (2001).
S. Niu et al., J. Am. Chem. Soc., 131, 5724–5725 (2009).
3
A. Dey et al., Science, 318, 1464–1468 (2007).
1
2

Acknowledgements

This work was supported by the Photon and Quantum Basic Research Coordinated Development Program, Quantum Leap
Flagship Program (Q-LEAP) JPMXS0120330644 from the Ministry of Education, Culture, Sports, Science and Technology(MEXT), PRESTO JPMJPR17G7 from the Japan Science and Technology Agency (JST), and Grants-in-Aid for Scientific
Research (C) JP20K06523, for Research Activity Start-up JP25891030 and JP20K22642 and for Young Scientists (B)JP15K18494 from the Japan Society for the Promotion of Science (JSPS).
159

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-02-02
Fabrication of a quantum sensor to reveal a topic in thermal physiology
Shuya Ishii1,2
Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology, 1233
Watanuki, Takasaki, Gunma 370-1292, Japan
2
Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 4-9-1 Ana-gawa, Inageku, Chiba 263-8555, Japan
1

Abstract
At first, I’ll talking about a topic of thermal physiology in myocardial contraction to introduce the importance of focusing
on temperature in biological viewpoint. During excitation-contraction coupling of striated muscle, sarcomeres are activated
via thin filament structural changes, i.e., from the “off” state to the “on” state, in response to a rise in the intracellular Ca2+
concentration. We systematically investigated the effects of rapid heating by infra-red (IR) laser irradiation on the sliding ofthin filaments reconstituted with human cardiac α-tropomyosin (Tm) and bovine ventricular troponin (Tn), or rabbit fastskeletal Tm-Tn complex in the in vitro motility assay. The findings in our studies suggest that the “on-off” equilibrium of
the cardiac thin filament state is partially shifted toward the “on” state in diastole at the body temperature, enabling rapid
and efficient myocardial dynamics in systole [1,2].
Next, I’ll show you a study of fabricating a quantum sensor (under submission), which has been getting a lot of attention
in biological field. Negatively charged nitrogen-vacancy (NV-) center in diamond is known as quantum sensor, can be used
to measure small changes in physical quantities, such as temperature [3]. Electron beam irradiation into type-Ib diamond is
known as a good method for the creation of high concentration negatively-charged nitrogen-vacancy (NV-) centers by whichhighly sensitive quantum sensors can be fabricated. In order to understand the creation mechanism of NV- centers, we study
the behavior of substitutional isolated nitrogen (P1 centers) and NV- centers in type-Ib diamond, with an initial P1
concentration of 40-80 ppm by electron beam irradiation up to 8.0 x 1018 electrons/cm2. P1 concentration and NVconcentration were measured using electron spin resonance and photoluminescence measurements. Comparing
concentration of P1 centers with that of NV- centers, it suggests that a part of P1 centers plays a role in the formation of otherdefects. The usefulness of electron beam irradiation to type-Ib diamonds was confirmed by the resultant conversion
efficiency from P1 to NV- center around 12-19%. The result obtained in this study is useful to understand the creation
mechanism of NV- centers, leading to realize highly sensitive quantum sensors.
Acknowledgement
This work was supported by Quantum Leap Flagship Program (Q-LEAP; JPMXS 0118067395) of MEXT.
Reference
1.
Oyama K, Mizuno A, Shintani SA, Itoh H, Serizawa T, Fukuda N, et al. Microscopic heat pulses induce
contraction of cardiomyocytes without calcium transients. Biochem Biophys Res Commun [Internet].
2012;417(1):607–12. Available from: http://dx.doi.org/10.1016/j.bbrc.2011.12.015
2.

Ishii S, Oyama K, Arai T, Itoh H, Shintani SA, Suzuki M, et al. Microscopic heat pulses activate cardiac thinfilaments. J Gen Physiol. 2019;151(6):860–9.

3.

Barry JF, Schloss JM, Bauch E, Turner MJ, Hart CA, Pham LM, et al. Sensitivity optimization for NV-diamondmagnetometry. Rev Mod Phys. 2020;92(1):015004(68).

160

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SE-03B-02-03
Investigation of irradiation induced nitrogen-vacancy centers in 5-nanometersized 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

2

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

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 formation mechanism in very small particles is still
limited. Here, the study was focused 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 in a series of nanodiamonds(5 - 100 nm), it was shown that the formation process in DNDs is unique in several aspects. NV- centers in DNDs are alreadyformed during electron irradiation, without the need for high-temperature annealing. The effect was interpreted in terms of“self-annealing”, where size and type dependent effects enable vacancy migration at lower temperature. Although NVconcentration increases with particle size, the NV- concentration in NDs surpasses that of 20 nm-sized nanodiamonds. Using
Monte-Carlo simulations, we show that the higher substitutional Nitrogen concentration compensates the vacancy loss
induced by the large particle surface. Upon 1.5 × 1019 e-/cm2 electron irradiation, DNDs show a 12.5-fold NV- incrementwith no sign of saturation. These findings can be of interest for the creation of defects in other very small semiconductor
nanoparticles.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644 & JPMXS0118067395, KAKENHI(Grants 20H00453, 18K19297)

MethodFigure 1. (a) Continuous-wave half-field EPR spectra of electron-irradiated (2 MeV, 5×1018 e-/cm2) nanodiamonds withdifferent particle size after high-temperature annealing. The double integral of the signal at geff = 4.227 provides the NVconcentration. (b) A summary graph of NV- content (ppm, in units of atomic ratio) in NDs of different sizes, measured via
the half-field EPR technique. Blue bars are the pristine nanodiamonds; Orange bars are the electron-irradiated nanodiamonds;
Yellow bars are the electron-irradiated and subsequently annealed nanodiamonds (derived from the geff = 4.227 signal in the
EPR spectrum of Fig. 1(a)). Electron irradiation was conducted with 2 MeV electrons at a fluence of 5×1018 e-/cm2;
Annealing was performed at 800 °C in vacuum for 2 h. All samples were boiling acid treated to remove Fe3+ impurities,
which overlap with the half-field EPR NV- signal. Inset table shows the corresponding NV- concentrations in ppm. Errors in
NV- concentration do not exceed ±15%.
161Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-02-04
Formation of flavin anion and tyrosine radicals in avian Cryptochrome4
Hiroaki Otsuka1, Hiromasa Mitsui1, Kota Miura1, Keiko Okano1, Yasushi Imamoto2, 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
Many animals, such as avian and insects, exhibit light-dependent
magnetoreception [1] that is likely mediated by the magnetic field-dependentchemical reaction of a pair of entangled radicals, called radical pair mechanism(RPM) [2].
Avian CRY4 is a plausible magnetoreceptor operating through RPM (FIG. 1)
in the retina [3,4]. Our previous study suggested that chicken CRY4 (cCRY4)
changes its conformation upon blue light irradiation [4] along with the formationof neutral radical FAD (FADH●) [5]. Together with the retinal localization of
CRY4, it is a leading candidate of magnetoreceptor in birds. Therefore, analysisof the molecular changes after photoreception by CRY4 will be a key step for
elucidation of RPM in the magnetoreception.
In this study, we measured the transient reactions up to the formation of FADH●
after photoreception of CRY4 by millisecond timescale spectroscopy. Singularvalue decomposition (SVD) was applied to detailed analysis of the photoreactions.
For comparative analysis, the recombinant CRY4 of magnetically migrating
European robin (ErCRY4) was prepared.

FIG. 1. Radical pair model
mediated by cryptochrome

CRYs photoactivation followed byformation of two entangled radicals are
assumed to detect the geomagnetic
field.

MethodRecombinant cCRY4 samples were purified by GST-tag purification system. Transient reactions of each sample were
measured by laboratory-built, time-resolved spectrophotometry system. Obtained data were decomposed by SVD analysis
and reconstructed into the spectra of each independent reaction (B spectra). SVD analysis yielded the spectrum representing
steady state difference spectrum (B0 spectrum) and the two spectra representing the spectral changes occurring up to steadystate (B1 and B2 spectra).
Results and discussion
Regardless of the presence of dithiothreitol (DTT), flavin anion radical (FAD●‒), a precursor of FADH●, was formed justafter the blue light irradiation of ground state of cCRY4 and ErCRY4 (having oxidized FAD: FADOX). FAD●‒ was thenprotonated to FADH● on the time scale of sub-seconds. In the absence of DTT, FAD●‒ was oxidized to FADOX more rapidly
than the protonation.
The spectral data were decomposed to three difference spectra (B0–B2) by SVD, representing two independent reactions;the oxidation and protonation. Time constants for the protonation from FAD●‒ to FADH● and the oxidation from FAD●‒ to
FADOX was 200 ms and 34 ms, respectively. Such a large difference in the time constants between the oxidation andprotonation suggests the bifurcation of FAD●‒ bound to cCRY4 and ErCRY4. Furthermore, the presence of tyrosine neutral
radical (Tyr-O●) was suggested by the spectrum for FAD●‒ oxidation in cCRY4. Based on these results, we speculate that
FAD●‒ could be paired with Tyr-O●, and that magnetoreception may be achieved by detecting the ratio of the state ofentangled [FAD●‒ Tyr-O●]. A comparison of photoreactions in cCRY4 and ErCRY4 would allow us to consider thedifferences in magnetoreception mechanisms between nesting and migrating birds.

Reference

R. Wiltschko and W. Wiltschko, Sens. Nat. 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).
1

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SE-03B-02-05

Do neural activities of binocular rivalry follow a quantum probability
model? A test of temporal Bell inequalities
Takahiro Hirao1,2, Naotsugu Tsuchiya3, Emmanuel Pothos4, Jerome Busemeyer5, Peter Bruza6, andMakiko Yamada1,21Institute for Quantum Life Science, National Institutes for Quantum Science and Technology
Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology
3
School of Psychological Sciences, Monash University
4
School of Arts and Social Sciences, Department of Psychology, City, University of London
5
Department of Psychological and Brain Sciences, Indiana University Bloomington
6
Faculty of Science and Technology, Queensland University of Technology
hirao.takahiro@qst.go.jp
Introduction
2

Binocular rivalry refers to a phenomenon in which the perceived image changes spontaneously over time when the twoeyes are presented with different images. The purpose of this study is to test whether the violation of temporal Bellinequality can be experimentally observed in binocular rivalry. If the temporal Bell inequality is violated (under nosignaling in time: NSIT), it implies that the perception of the rival stimuli cannot be assumed to be definite at each point
in time (i.e., “realism” in the corresponding mental representations is violated), which is a key indication of non-classicalbehavior (as in, for example, quantum-like systems) [1]. Here, to test the violation of the inequality, we used binocular
rivalry and measured both subjective reports and electroencephalogram (EEG). With EEG, we used frequency-tagging
technique to track the cortical signal driven by each eye’s stimulus, known as the steady-state visual evoked potential(SSVEP). We present the conceptual and methodological approaches to test the temporal Bell inequality.

MethodTwo checkerboards flickering at different frequencies (red stimulus at 7.5 Hz; blue stimulus at 6.6 Hz) weredichoptically presented, one to each eye [FIG. 1(A) (B)]. Participants were asked to report their perception of the rival
stimuli at two out of three different timepoints [FIG. 1(C)]. The electroencephalogram (EEG) was recorded from 28 scalp
sites at a sampling rate of 1000 Hz. The EEG was re-referenced to the averaged mastoids and band-pass filtered with a
0.1-50 Hz cutoff. The prominent artifacts were identified and removed by the individual component analysis. The SSVEP
signals were extracted by using an adaptive recursive least-square (RLS) filter [FIG. 1(D)].

FIG. 1. (A) Schematic illustration of the task for a block. A participant conducted a total of 10 blocks. (B) Time-course
modulation of checkerboard patterns. (C) Three timings on the measurement of perceived stimuli. The perceived stimulus
was measured at two out of three timepoints for the calculation of the temporal Bell inequality. (D) Steps for SSVEP
calculation using a 30-second binocular rivalry data. An adaptive RLS filter was applied to the raw EEG data in the top
figure. In the middle figure, the extracted frequency-tagged amplitudes of 7.5 and 6.6 Hz were depicted. The bottom
figure indicates that the frequency-tagged amplitude extracted by SSVEP was consistent with the subjective report.

Reference

H. Atmanspacher, and T. Filk, J. Math. Psychol. 54, 314-321 (2010).

1

Acknowledgement

This work was supported by JSPS KAKENHI JP20H05711 and MEXT Q-LEAP Grant Number JPMXS0120330644.

163

Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-02-06
X-ray absorption spectroscopy of a silicon phthalocyanine derivative, IR700, for
X-ray excited photoimmunotherapy
Y. Izumi1, M. Ohara1, K. Fujii1, A. Yokoya1, R. Watanabe1, K. Nakagawa2, O. Inanami3, T.
Taketsugu4, and M. Ogawa5
1

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

Graduate School of Engineering, The University of Tokyo

3

Graduate School of Veterinary Medicine, Hokkaido University
4

5

Faculty of Science, Hokkaido University

Graduate School of Pharmaceutical Sciences, Hokkaido University
izumi.yudai@qst.go.jp

Introduction
Photoimmunotherapy (PIT) has been recognized as one of the most promising methods in advanced cancer therapies [1].
A silicon phthalocyanine derivative (IR700) conjugated to a monoclonal antibody (mAb) targeting epidermal growth factor
receptors of cancer membranes is used as a photosensitizing molecule. Irradiating the mAb-IR700-bound cancer cells withnear-infrared (NIR) light, axial ligands of the IR700 are released. It makes the cell membranes brittle and, as a result, prompts
cell death. Though the evidence clearly shows a strong potential of the PIT, the short penetration depth of NIR (a few
centimeters) might be controversial when it is applied to deeply located tumors. We have focused on X-ray-induced corelevel excitations as alternative initiation probes owing to those long penetration depths. In this work, the reaction probabilityof the IR700 with X-rays was evaluated by measuring atom selective K-shell X-ray absorption spectra using a synchrotron
radiation soft-X-ray beamline.

Methods

Thin films of IR700 were prepared on gold plates by drying an aqueous solution of IR700 at room temperature. X-ray
absorption spectroscopy of the films was performed in the BL23SU at SPring-8 in Japan. The absorption spectra were
measured in the nitrogen, oxygen, and silicon K-edge energy regions, in which corresponding K-shell electrons were excited
selectively. The optical absorption cross-section in each region was evaluated.

Results and Discussion

The absorption cross-section of the oxygen K-shell resonance excitation σr (~536 eV) was almost two folds of that at thepre-edge region σp (~530 eV) in which the oxygen atoms were not excited (FIG. 1). It was larger than those of the nitrogenand silicon K-shell resonance excitations.
X-ray-induced bond breakages often occur in the vicinity of the excited atoms. Since the axial ligands and thephthalocyanine body of the IR700 are linked via oxygen atoms, the oxygen K-shell excitations could be effective to detachthe axial ligands, similar to the NIR irradiations.

FIG. 1. X-ray absorption spectrum of the IR700 thin film in the oxygen K-edge energy region.
Reference
1
M. Kobayashi et al., ChemPlusChem, 85, 1959 (2020).
164Proc. 4th IFQMS (The 4th International Forum on Quantum Metrology and Sensing)

SE-03B-02-07
Magnetically sensitive radical pairs in avian cryptochrome 4 proteins
Presenters: Jingjing Xu1, Siu Ying Wong2
1

Institute of Biology and Environmental Sciences, Carl-von-Ossietzky University Oldenburg,
2

Department of Physics, Carl-von-Ossietzky Universität Oldenburg,
jingjing.xu@uni-oldenburg.de*A list of authors and affiliations appears on the next page.

Introduction
Migratory birds use the earth’s magnetic field to navigate during their spectacular migratory journeys1. The avian magnetic
compass was proposed to be based on quantum effects in radical pairs (RP) in cryptochrome (CRY) proteins2,3. Specifically,transfer of an electron along a chain of tryptophan residues to the photoexcited chromophore, flavin adenine dinucleotide(FAD), in CRY generates a spin-correlated flavin-tryptophan radical pair. An external magnetic field could alter the timedependent fractions of RPs present in the singlet and triplet states and change the product yields of spin-selective RP chemical
reactions4. However, there had been no experimental evidence showing a magnetic sensitivity of CRY proteins from any
migratory bird.

MethodCryptochrome 4 proteins from the migratory European robin (Erithacus rubecula, ErCRY4) and non-migratory birds
pigeon (Columba livia, ClCRY4) and chicken (Gallus gallus, GgCRY4) were produced using an E.coli expression system.
Magnetic field effects on CRY4 proteins were measured optically using various spectroscopic techniques, including
picosecond transient absorption spectroscopy, cavity ring-down spectroscopy, broadband cavity-enhanced absorption
spectroscopy, and electron paramagnetic resonance.

Results
A long-lived spin-correlated radical pair is formed via light-induced electron hopping along a tetrad of tryptophan residues
to FAD in European robin CRY4 (FIG. 1A and 1B). ErCRY4 is more sensitive to weak magnetic fields than the plant CRY
given other factors being equal, e.g., pH7 and tryptophan-triad (FIG. 1C). Moreover, ErCRY4 shows a more pronounced
magnetic field effect than non-migratory pigeon and chicken CRY4s (FIG. 1D).

FIG. 1. A light-induced magnetically sensitive radical pair in cryptochrome proteins. A, Structural homology model ofEuropean robin CRY4 (ErCRY4) showing sequential electron transfer from tryptophan residues (Trp, W) to the FAD. Inset
shows a robin and a CRY4 protein sample with FAD bound. B, Time-resolved X-band (9.75 GHz) electron paramagnetic
resonance spectra of wild-type ErCRY4 and the terminal tryptophan mutant (WDF) recorded at 1 °C, 0.5 μs after a 450-nm
laser pulse. In the ErCRY4 WDF mutant, the fourth tryptophan was replaced by a redox-inactive phenylalanine residue toblock the fourth electron transfer step. C, Comparison of magnetic field effects on ErCRY4 WDF and Arabidopsis thaliana
cryptochrome (AtCRY). B1/2 is the intensity of a magnetic field that produces 50% of the overall magnetic field effect. D,
Change in the optical absorbance of photoinduced radicals in three avian CRY4 samples induced by a 30-mT magnetic field.
ErCRY4 spectra are shown at two different times after the start of illumination.

Conclusion:
Cryptochrome 4 from the European robin is magnetically sensitive in vitro and could be the long sought-after magnetic
sensor in night-migratory songbirds.

Reference

H. Mouritsen, Nature 558, 50-59 (2018).
K. Schulten, et al., Z. Phys. Chem. 111, 1-5 (1978).
3
T. Ritz, et al., Biophys. J., 78, 707-718 (2000)
4
P. J. Hore & H. Mouritsen, Annu. Rev. Biophys. 45, 299-344 (2016),
1
2

165

Authors:
Jingjing Xu1+, Lauren E. Jarocha2+, Tilo Zollitsch2+, Marcin Konowalczyk3+, Kevin B. Henbest2,3+, Sabine Richert4+, Matthew J.
Golesworthy3+, Jessica Schmidt1, Victoire Déjean3, Daniel J. C. Sowood2, Marco Bassetto1,2, Jiate Luo2, Jessica R. Walton2, Jessica
Fleming2, Yujing Wei2, Tommy L. Pitcher3, Gabriel Moise3, Maike Herrmann1, Hang Yin5, Haijia Wu6, Rabea Bartölke1, Stefanie J.
Käsehagen1, Simon Horst1, Glen Dautaj1, Patrick D. F. Murton2, Angela S. Gehrckens2, Yogarany Chelliah7,8, Joseph S. Takahashi7,8, KarlWilhelm Koch6,9, Stefan Weber4, Ilia A. Solov’yov9,10*, Can Xie11*, Stuart R. Mackenzie2*, Christiane R. Timmel3,12*, Henrik Mouritsen1,9*,P. J. Hore2*
AG Neurosensory Sciences/Animal Navigation, Institut für Biologie und Umweltwissenschaften, Carl-von‐Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany

1

Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory,Oxford OX1 3QZ, UK

2

Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford OX1 3QR, UK

3

Institut für Physikalische Chemie, Albert‐Ludwigs‐Universität Freiburg, 79104 Freiburg, Germany

4

Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA

5

Division of Biochemistry, Department of Neuroscience, Carl-von-Ossietzky Universität Oldenburg, DE-26111 Oldenburg, Germany

6

Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA

7

Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX75390-9111, USA

8

Research Centre for Neurosensory Science, University of Oldenburg, 26111 Oldenburg, Germany

9

Department of Physics, Carl-von-Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany

10

CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of11

Sciences, Hefei, Anhui 230031, PR China
Centre for Advanced Electron Spin Resonance (CAESR), Department of Chemistry, University of Oxford, Oxford OX1 3QR, UK

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