01

Message from the Director

We at NTT Basic Research Laboratories (BRL) are extremely
grateful for your interest and support in our research activities
during the last year.
Our laboratories central mission is to promote breakthroughin science and innovations in leading-edge technology that canadvance NTT's long-term business, overcoming current limitationsin speed, size, and of course energy consumption.
To achieve this, our scientists & engineers in the fields of physics,
chemistry, biology, mathematics, electronics, informatics, andmedicine, conduct fundamental research in material, physical, andquantum science.
An "open door" management policy allows us to collaborate
with many universities and research institutes from all over
the world, as well as other laboratories within NTT, further
enhancing our ability to achieve our missions. We have regularlyorganized international symposiums, seminars, and various type ofworkshops at our Atsugi R&D center to disseminate our researchachievements and communicate with fellow scientists, engineers
and the public.
All of these activities enable us to realize our "open door" policy
and mission.
Your continued support would be highly appreciated.

Dr. Kazuhide Kumakura
Vice President, Head of NTT Basic Research Laboratories

02

Activity Report

Advisory Board
The NTT BRL Advisory Board, whichw a s f i r s t c o n v e n e d i n 2001 , h e l d
its 12th meeting on February 2 - 3,2023. The aim of the Advisory Board
is to provide an objective evaluationof our research plans and activities
to enable us to employ strategic
management in a timely manner. At
this meeting, the BRL researchers
had a lunch and a poster session
with the board members, where
they had chances to present theirresearches to the board members ina casual atmosphere.

N T T- B R L S e m i n a r
We invite distinguished researchers in the world
to hold an in-house seminar. This year, we had 23
seminars dedicated to our research field and sharedlatest research results with the guests.

Front image:

On-chip biological model
Technology to artificially reproduce advanced biological functions such as organs by
culturing cells in vitro is attracting attention in a wide range of fields including cell biology,
regenerative medicine, drug discovery, and food development. If we can create an on-chipbiological model that can reproduce biological functions on a sensor chip, it will be possible
to obtain multifaceted information at the cellular level, which is expected to lead to theconstruction of a "biodigital twin" that maps us on a digital space using the information.
NTT Basic Research Laboratories has developed unique technologies
for on-chip shape control of bio-friendly thin-film materials (grapheneand hydrogel). These various platform technologies enable to constructon-chip biological models such as a brain model that can simulate
and analyze the structure and function of brain neural networks whencombined with neurons [upper left], and an intestine model that canperform peristalsis and segmental movement mimicking an intestinal tractby dynamically shape controlling the flow path structure [lower right]

Riku Takahashi (left)
Engaged in basic technology research usinghydrogels composed of water and polymer networks
Koji Sakai (right)
Engaged in research on culture models of the nervous
system based on electrode fabrication technology

03

Organization

NTT Basic Research Laboratories

Director

Kazuhide Kumakura

Research Planning Section

Multidisciplinary Materials Design and Science Laboratory

Advanced Applied Physical Science Laboratory

Quantum Science and Technology Laboratory

Executive Manager

Executive Manager

Executive Manager

Executive Manager

Katsuya Oguri

Hideki Yamamoto

P5●Nanodevices Research

Research Group●Low- Dimensional
Nanomaterials Research
Group●Molecular and Bio Science
Research GroupGroup●Nanomechanics ResearchGroup●Quantum Optical Physics
Research Group●Photonic Nano-Structure
Research Group●Researchers (Foreign Researchers)…94（6）●Research Associate/Specialist…7●International Interns…11＊●Domestic Interns…7＊●Guest Researchers…1＊

P7●Thin-Film Materials

The population data of NTT-BRL members●Joint Researcher…17

Katsuya Oguri＊…Jan. to Dec. 2023 total

Hiroki Takesue

P9●Quantum Optical State

Control Research Group●Theoretical Quantum

Physics Research Group●Superconducting Quantum

Circuits Research Group●Quantum Solid State

Physics Research Group04
As of Dec. 31, 2023

Advisor y Board

Chalmers University of Technology, Sweden

Max-Planck-Institut für Festkörperforschung,Germany

University of Illinois at Urbana-Champaign,USA

Imperial College,UK

Université Pierre et Marie Curie,France

The University of Texas at Austin,USA

Forschungszentrum Jülich, Germany

CEA Saclay, France

University of Twente, Netherlands

Prof. Per Delsing

Prof. Sir Anthony J. Leggett

Prof. Klaus von Klitzing

Prof. Sir Peter Knight

Prof. Elisabeth Giacobino

Prof. Andreas Offenhäusser

Prof. Allan MacDonald

Prof. Christian GlattliProf. Dave H.A. Blank

Nanophotonics Center

Research Center for Theoretical Quantum Information

Bio-Medical Informatics Research Center

Project Manager

Project Manager

Project Manager

Masaya Notomi

P11

Seiichiro Tani

P11

Hiroshi Nakashima

P11

Research Professors

Sakakibara Heart Institute, Advisor

Tohoku University

University of Toyama

Prof. Hitonobu Tomoike

Prof. Masao Morita

Prof. Kiyoshi Tamaki

Tohoku University, Professor Emeritus

Hiroshima University

Prof. Junsaku Nitta

Prof. Hideki Gotoh

05

Multidisciplinar y Materials Design and Science Laborator yGroups and Research Themes

Multidisciplinary Materials Design andScience Laboratory
Overview
T h e a i m of t h e M u lti d is c i p li n a r y M a te ri a l s D e s ig n a n d
Science Laboratory is to contribute to progress in materials
science a n d to revolutio nize informatio n commu nicatio ntechnolog y by creating novel materials with various
internal degrees of freedom (lattice, charge, spin, orbital,etc.) through materials design and synthesis beyond
c o nve n ti o n a l c o n c e p t s of c l a s s if i c a ti o n s , d i m e n s i o n s ,scales, and synthesis methods. The research groups that
constitute this laboratory are investigating a wide rangeof materials including semiconductors, superconductors,
m a g n e t i c m a t e ri a l s , t o p o l o g i c a l m a t e ri a l s , c o n d u c t i v epolymers, and biological soft materials. We are conducting
innovative materials research based on advanced thin-filmgrow th te ch n ologies , high - p re cisio n a n d high - resolutio nmeasurements of structures, properties along withtheoretical studies, and data science (informatics).

Multi-source molecular beam epitaxy apparatus:
an enabling technology for high-quality thin films
of complex oxides/nitrides, which is also exploited
as a synthesis method sui generis for novel
superconductors and magnetic materials.

Thin-Film Materials Research Group
Novel Semiconductor Devices

Creation of light- emitting devices over a wide range from
D U V to N I R , high - ef ficiency energ y conversion devices ,hig h - p owe r d evic e s , a n d n ovel m ultif u n ctio n al (o ptic al,
electric, and spintronic) devices

Low-Dimensional Nanomaterials ResearchGroup
2D atomic-layer Materials

Creation of ultimately thin functional atomic-layer materials
for next-generation electronics

Complex Oxide Thin Films

C re a tio n of t ra il b la zi n g s u p e rc o n d u cto r s a n d m a g n etic
materials beyond conventional concepts

Molecular and Bio Science Research Group
Biocompatible Electrode Materials

Development and application of bioelectrode materials formeasurement of deep biological information

Bio-devices
Creatio n of bio -fu n ctio nal mim etic d evices exploiting
biomolecules, cells, and soft materials

06

Achievements in 2023

EN

Evaluation value of SrTiO3Change in prediction by the prior mean value

Prediction
with m+Large prior mean m＋→ Large prediction value in unexplored regions
Small prior mean m → Small prediction value in unexplored regions(Left) Change in prediction due to the prior mean value(Right) Electron microscopy image of a stoichiometric SrTiO₃ thin film

Schematic illustration of real-time optical observation system for thermal CVD (right)
and optical reflection micrograph of graphene on Cu substrate (left).

S t o i c h i o m e t r i c G r o w t h o f S r T i O₃ F i l m s v i a
Bayesian Optimization with Adaptive Prior Mean

Real-time Observation of Graphene CVD
Growth Using Ultraviolet Reflection

To efficiently optimize the growth parameters for synthesizing
thin oxide films, we developed a new method based on a
statistical machine learning technique called Bayesian
optimization (BO). We then used it to synthesize high-quality
thin films of SrTiO₃, a candidate material for next-generation
high-k capacitors and photocatalysts. Whereas conventional
BO has a problem of focusing too much on searching within acertain region that shows good evaluation values rather thanaround the global optimal region of the evaluation value, the
new BO method encourages exploration of a larger area byadapting the prior mean of the prediction model to escape fromthe local optimal region.

T w o - d i m e n s i o n a l (2 D ) m a t e r i a l s s u c h a s g r a p h e n e a r e
promising for the next generation of devices. Here, we
performed a real-time observation of graphene growth on aCu substrate by using ultraviolet (UV) reflection during thechemical vapor deposition (CVD) process. This observation
method improves the controllability and reproducibility of thegrowth process of high-quality 2D materials and thereby will
foster their device applications.

Y. K. Wakabayashi, T. Otsuka, et. al., APL Mach. Learn. 1, 026104 (2023).
Y. K. Wakabayashi, T. Otsuka, et. al., APL Mater. 7, 101114 (2019).

Y. Ogawa, T. Tawara, and Y. Taniyasu, ACS Appl. Nano Mater. 6, 21405 (2023).

Brain on a chip
Graphene
Parylene-C
Graphene

Self-folding of thin film
Formation of 3D cellular construct
Recording time (s)Modular 3D neuronal network
on self-folding electrode array&RFXOWXULQJ HQGRWKHOLDO DQG
VPRRWK PXVFOH FHOOVZLWKLQ
Self-folded film
WKHVHOIIROGLQJILOPWRPLPLF Endothelial
WKHVWUXFWXUHRIVPDOODUWHU\ Smooth muscle
NucleiSmoothmuscle cells

Electrode no.

(OHFWURGH
1HXURQ

Blood vessel on a chip

&XOWXULQJQHXURQVRQDVHOIIROGLQJILOPHOHFWURGHDUUD\WRUHFRUGWKHVSDWLRWHPSRUDO
SDWWHUQRIVLJQDOVIURPWKH
GHYHORSHGQHXURQDOQHWZRUN

Synchronized/ Random activities

Endothelial cells

Porousself-folding film
Smooth muscle

Porousextracellular matrix

Endothelium(Upper left) Staining image of encapsulated 3D neuronal aggregate andrepresentative recorded neuronal signal(Lower left) Schematic images of self-folding electrode array and modular 3D
neuronal network(Lower right) Activity patterns recorded from modular 3D neuronal network(Left) Schematic images of artery-mimicking cell culture using cell encapsulation
method(Upper right) Staining image of co-cultured vascular endothelial and smooth muscle
cells(Lower right) Control of curvature radius of tubular tissue by adjusting film thickness

Self-folding Electrode Array for Recordingfrom a Modular 3D Neuronal Network

Small-artery-mimicking Cell Culture Using
Porous Self-folding Film

We previously studied a self-folding graphene-based electrode
that can encapsulate living neurons within a folded structure.
In this study, we developed a self-folding electrode array thatallows for simultaneous formation of neuronal 3D aggregate
inside each folded electrode and enables us to record neuronal
activities from a neuronal network consisting of interconnected
aggregates. We also demonstrated that the brain-like structuralfeatures, including three-dimensionality and modularity, of thisneuronal network affect a variety of activity patterns with amixture of synchronized and random activities.

We encapsulated vascular cells within a self-folding porous
film to form a tubular vessel-like cellular construct. To mimic
the structural features of small arteries that important in
vascular pathology, we formed a 10-micrometer-scale tubular
construct by utilizing the curvature tunability of self-folding film
while co-culturing endothelial cells that uptake nutrients fromblood and smooth muscle cells that generate driving force forvasoconstriction. The porous film emulates the extracellularmatrix between endothelial and smooth muscle cells andreproduces the microenvironment of small arteries in which
their cellular interaction is modulated by pores.

K. Sakai, T. F. Teshima, T. Goto, H. Nakashima and M. Yamaguchi, Adv. Funct. Mater. 33, 2301836 (2023).

K. Sakai, S. Miura, T. F. Teshima, T. Goto, S. Takeuchi and M. Yamaguchi, Nanoscale Horiz. 8, 1529 (2023).

Multidisciplinary Materials Design and Science Laboratory

Prediction 1 nmwith m-07

Advanced Applied Physical Science Laborator yGroups and Research Themes

Advanced Applied Physical Science
Laboratory
Overview
T he Advanced A pplied Physical Science L aboratory has
lau nched towa rds the creatio n of in novative informatio ncommunication technologies and future functional devices
that bring long-term value for the accelerating technologyd r i v e n s o c i e t y. L e a d i n g r e s e a r c h g r o u p s i n t h e f i e l d sof nanoelectronics, nanomechanics, nanophotonics,
spintronics, and quantum electronics are closelycollaborating for this exciting challenge. We will pioneer theforefront of the applied physical science field and discovernovel functionalities in solid-state quantum systems basedon our nanofabrication technology, advanced measurement
technology, and light-wave technology.

Nanodevice Research Group

Single-electron Devices for Ultimate Electronics
Highly accurate, highly sensitive, and low- power devices
based on single charge transfer and detection

Nanodevices with Novel Functions

Novel and high performance nanodevices based on silicon
and hybrid materials

Nanomechanics Research Group

Semiconductor Opto/electromechanics
Novel devices using mechanical functionality insemiconductor fine structures

Phonon Manipulation

P r o p a g a t i o n c o n t r o l o f a c o u s t i c w a ve s u s i n g a r t if i c i a l
structures

Quantum Optical Physics Research Group

Ma nip ulation of Ult rafast a n d Ult ra - st a ble L ase r
Field
Ultrafast physics investigated by attosecond spectroscopy,
Optical-lattice clock network

Nano-scale Physics in Optically-active Materials
Physics related to photons, excitons, and spins, insemiconductor nanostructures and rare-earth oxides

Photonic Nano-Structure Research Group
Integrated Nanophotonics Technologies

Ultra - compact and ultra -low power photonic devices andcircuits, novel photonic phenomena in nanostructures

Laser cooling system for optical lattice clocks:
Laser system used for cooling and trapping(magneto-optical trap) of strontium atoms.

08

Achievements in 2023

f

Insulator
Gate

Vg

IP

A

SE
collision
Left pump
Siliconf

Right pump
Electron potential:Single electron (SE) e

Pump current during single-electron collisions. The current exceeded the current
generated from the left pump (elementary charge e × clock frequency f). Inset:
Schematic diagram of the device and part of the electrical measurement system.

Schematic of the acoustic-impedance matched GHz acoustic device (left). Crosssectional SEM image (upper right) and resonance characteristics (lower right) of
the device.

Coulomb Collisions of Single Electrons in
Series-coupled Silicon Single-electron Pumps

Title: Realization of an Impedance-matched
GHz Acoustic Device

Investigation of the Coulomb interaction between single electrons
in a silicon single-electron pump, which can transfer single
electrons accurately, is important for improvement of the transfer
accuracy and for the quantum manipulation of single electrons,
but so far there have been no observations of this interaction.
Here, we connected two silicon single-electron pumps in series
and collided a single electron emitted from the left pump with asingle electron trapped in the right pump. As a result, the current
increase due to the single-electron emission in the right pump dueto the Coulomb interaction during the collision could be observed.
This is the first observation of the Coulomb interaction in a silicon
single-electron pump and is an important insight for developing
electric standards and quantum devices.

Aluminum nitride (AlN) has a high speed of sound andpiezoelectricity and is used in acoustic devices such as highfrequency filters. AlN acoustic devices that use bulk acoustic waves
consist of an AlN thin film sandwiched by metal top and bottom
electrodes grown on a crystal substrate. However, an acousticimpedance mismatch due to the insertion of metal layers has beena problem with these devices. In this study, we developed a highquality and impedance-matched acoustic device operating in the
GHz range by directly growing AlN thin film on a conductive SiC
substrate acting as a bottom electrode.

G. Yamahata, N. Johnson, and A. Fujiwara, Physical Review Applied 20, 044043 (2023).

(b)

Bi

Enhancedmagnetic field Fast precession

Time (ns)20983

Spin injection &diffusion

Si Air hole
Suppressedmagnetic field Slow precession

Kerr rotation(arb. units)
1

0.5

0
-1
0.0
-30

0

x (µm)

30(a) Schematic structure of sample in which Bi atoms are incorporated in GaAs(b) Spatiotemporal mapping of the magneto-optical Kerr effect. The spin
precession frequency, which appears as red and blue oscillations, changes withthe probe position x, as a result of the enhanced spin-orbit interaction.

Enhancement of Spin Manipulation Efficiency
by Incorporation of Bismuth Atoms into
Gallium Arsenide
The incorporation of a small amount of bismuth (Bi) atoms into
gallium arsenide (GaAs) enhances the spin-orbit interaction,
which is known to produce a non-real (effective) magnetic
field that is experienced by the electrons moving in an electricfield. This phenomenon is due to the strong local electricfield generated by the heavy bismuth atoms at the interface
between the GaAs and GaAsBi layers. Such an effective strong
magnetic field generated by the spin-orbit interaction enables
us to manipulate spins more quickly in smaller areas, creatinga new avenue for developing spintronics with highly efficient
control of spins.

Y. Kunihashi, Y. Shinohara, S. Hasegawa, H. Nishinaka, M. Yoshimoto, K. Oguri, H. Gotoh, M. Kohda, J.
Nitta, and H. Sanada, Appl. Phys. Lett. 122, 182402 (2023).

(a)

R1
s1
s2

(b) 1.0
Normalized power(a)M. Kurosu, D. Hatanaka, R. Ohta, H. Yamaguchi, Y. Taniyasu, and H. Okamoto, Appl. Phys. Lett. 122,
122201 (2023).

0.8
0.6
0.4
0.2

0.0
190.4305

1 μm

Qexp = 1.1×106
190.4315
190.4325
Frequency (THz)(a)Schematic design of single-point-defect PCN. The cavity Q factor is optimized
by varying the radii R1 of the holes nearest to the defect and two hole-layer shiftparameters (s₁, s₂).
(b)Device image and optical transmission spectrum of our cavity samples. By
calculating the ratio of the measured peak frequency and linewidth, the Q factor
was estimated to be 1.1×10⁶.

Ultrahigh-Q Single-point-defect Photonic
Crystal Nanocavity
A small single-point-defect photonic crystal nanocavity (PCN)
is suitable for composing large-scale arrays in various forms.
However, its light confinement capability has been weaker thanthose of other PCNs. By controlling the radii of the air holes
closest to the defect and the radial shift of the two hole layers
around the defect, we have improved its theoretical cavity
quality (Q) factor to 4.5×10⁸, which is two orders of magnitudelarger than the previous record value. It is still consideredin principle infeasible to obtain such an extremely high Q
value for PCNs in an experiment. Nonetheless, our samples
had Q factors over one million (termed the ultrahigh-Q level),
unprecedented values for this type of PCN. These results
suggest that our PCNs have potential for device applications.

K. Takata, E. Kuramochi, A. Shinya, and M. Notomi, Opt. Express 31, 11864 (2023).

Advanced Applied Physical Science Laboratory

Current
increase

09

Quantum Science and Technology Laborator yGroups and Research Themes

Quantum Science and Technology
Laboratory
Overview
T h e Q u a nt u m S cie n c e a n d Te c h n o l o g y L a b o ra to r y willcontribute to the exploration of the quantum science field
and the development of new technologies for overcomingth e co nve ntio nal info rmatio n p ro cessing limits withq u a n t u m - e n a b l e d d evi c e s a n d s y s te m s . W it h q u a n t u minformatio n theor y a nd our experimental research inphotonic, semiconductor, and superconducting systems asa basis, we aim to achieve new technologies in the areasof quantum communication , quantum sensing , opticaloscillator-based computing, and quantum computing basedon superconducting circuits and topological phenomena.

Q ua ntum Optical State Cont rol Resea rch
Group
Photonic Quantum Communication

Control of quantum state of light and its application to novelcommunication systems

No n -vo n Ne u m a n n Com p u t at io n Usi n g Q u a n t u m
OpticsNew computers based on coupled optical oscillators

Theoretical Q ua ntum Physics Resea rch
Group
Theoretical Quantum Information Science

Proposal and systematic design of quantum computation,communication, network and metrology schemes includingarchitectures.

Superconducting Quantum Circuits Research
Group
Superconducting Quantum Circuits

Manipulating quantum states using superconducting
devices

Ultimate Quantum Measurement and Sensing

Highly sensitive measurement technologies using quantum
mechanical effects

Quantum Solid State Physics Group

Quantum Transport in Hetero- and Nano-structures
based on Semiconductor and 2D Materials
Unconventional charge and spin transport phenomena inquantum devices

Fast Coherent Carrier Dynamics in Electronic Devices
Information processing with coherent electron motion3

He/4 He dilution refrigerator used to carryout low-temperature (below 100 milli-kelvins)
experiments for superconducting andsemiconductor quantum devices.

10

Achievements in 2023

(a)

|𝐷𝐷𝐷𝐷|

𝑆𝑆𝑆𝑆𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 /log 𝑁𝑁𝑁𝑁𝜃𝜃𝜃𝜃/𝜋𝜋𝜋𝜋

Coupling Strength

Oscillator Index Oscillator Index(c)

Coupling Angle / πTime [ms](a) Schematic diagram of photonic neuromorphic oscillators coupled bymeasurement-feedback.
(b) Experimental results on (upper) time evolution of rotational phase θ of eachneuron and (lower) local curvature of the phase ｜D｜in a chimera state.
(c) Theoretical phase diagram of partial synchronization in a complex oscillatory
network.

Creating and Detecting Chimera States in
Optical Oscillator Networks
The chimera state, a phenomenon where synchrony andasynchrony coexist in an oscillatory system, has attracted muchattention from researcher because of its relation to the complex
oscillatory dynamics in brain neuronal networks. Here, we madecoupled photonic neuromorphic oscillators that emulate certain
functionalities of brain neurons and generated a chimera stateaccompanying spontaneous changes in the functionality ofeach optical neuron. Furthermore, we developed a data-driven
method to detect chimeras hidden in complex oscillatory data
by regarding asynchronies as being analogous to vortices. Our
results will pave the way for developing an experimental andtheoretical platform to study brain function, brain diseases, andneuromorphic information processing.

T. Makinwa, K. Inaba, T. Inagaki, Y. Yamada, T. Leleu, T. Honjo, T. Ikuta, K. Enbutsu, T. Umeki, R. Kasahara, K. Aihara,and H. Takesue, Commun. Phys. 6, 121 (2023).
Y. Yamada and K. Inaba, Phys. Rev. E 108, 024307 (2023), Featured in Physics.

(a)
ne

10 μm

Sil

ico

ns

ns

MW

ub

μm

lin

e

bit

Qu
UID

SQ

str

T. Hatomura, SciPost Phys. 15, 036 (2023).

(b)
Ne

Readout

10

Time Rescaling of Nonadiabatic Transitions
Quantum simulation is a promising technology that enables
us to simulate large quantum systems. However, real quantum
simulators have limitations on their simulatable timescale. So
far, researchers have not been able to simulate slow dynamics
because of the short coherence time or fast dynamics becauseof a lack of a means to control the speed. Here, with the goal of
improving the usability of quantum simulators, we developed amethod to fast-forward and slow down the dynamics of interest.

uro

le

ry
Pa

Quantum simulators have limitations on their simulatable timescale, but we cansimulate slow dynamics by fast-forwarding it and simulate fast dynamics byslowing it down.

ate(a) Overview of magnetometry system using a superconducting flux qubit
for measuring electron spins in biomaterials.
(b) Temperature dependence of the magnetic field generated by ferricions in neurons and in a reference sample.
T h e f i g u r e s w e r e c r e a t e d b y m o d i f y i n g t h e o r i g i n a l p a p e r u n d e r C C B Y 4 .0 .

Fractional-integer quantum Hall junction

Electron Spin Detection in Biomaterials byUsing a Superconducting Flux Qubit

Charge-neutral-mode Transport in Fractional
Quantum Hall Edge StateWe detected ferric ions in neurons with a spatial resolution at
the single-cell level by using a superconducting flux qubit asa sensitive magnetometer. This method can also be used inquantitative analysis, as the detected signal intensity is directly
related to the number of electrons of the ions in the sample. In
addition, we identified the species or valence of ions by using
electron spin resonance spectroscopy. This method paves theway for imaging distributions of atoms in tissues at the singlecell level.

Edge transport in topological systems has potential
applications in quantum information processing and in
novel devices because of its robustness to perturbations. In
particular, researchers are interested in fractional quantum
Hall states owing to the presence of fractionally charged
quasiparticles. Here, we demonstrated the emergence of acharge-neutral mode in systems with strongly coupled ν = 1/3
fractional and ν =1 integer edge channels. Our study provides
fundamental knowledge for understanding quantum transport invarious topological systems.

H. Toida, K. Sakai, T.F. Teshima, M. Hori, K. Kakuyanagi, I. Mahboob, Y. Ono, and S. Saito, Commun.
Phys. 6, 19 (2023).

M. Hashisaka, T. Ito, T. Akiho, S. Sasaki, N. Kumada, N. Shibata, and K. Muraki, Phys. Rev. X 13, 031024 (2023).

Q u a n t u m S c i e n c e a n d Te c h n o l o g y L a b o r a t o r y

(b)

11

Nanophotonics Center

Nanophotonics Center

Nanophotonics Center

Overview
T h e N a n o p h oto nic s C e nte r was esta blis h e d in A p ril
2 012 a n d i s c o m p o s e d o f s e v e r a l g r o u p s i n v o l v e din nanophotonics research at NT T Basic Research
L a b o rato ries a n d N T T D evic e Te c h n olog y L a b o rato ries .
We are conducting studies of photonic crystals to reduce
the footprint and energy consumption of various photonic
d evices , such as o ptical switches , o ptical memories ,modulators , lasers , and photo - detectors . We are also
studying various photonic nanostructures to greatly enhancelight-matter interactions, and exploiting photonic integrated
circuits and devices for on-chip signal processing.
Research Themes
Extreme enhancement of light-matter interactions by using photonic
crystals and plasmonics● Integrable nanophotonic devices with extremely small energy
consumption● Novel optical platforms using nanomaterials and nanophotonics● Nanophotonic computations with photonics-electronics convergence●

Research Center for Theoretical Quantum Information

Research Center for Theoretical Quantum Information

Research Center for Theoretical Quantum Information

Overview
The research center was established in October 2023 by expansively
reorganizing the Research Center for Theoretical Quantum Physics,
in order to further strengthen the theoretical research on quantum
information science by facilitating interdisciplinary collaborationa m o ng rese a rch e rs in dive rse laye rs in th e re alm of q u a ntu m
information. We are aiming to become a“compass”of quantum
information that points to the correct direction in which the progressof q u a ntu m info rmatio n te ch n olog y, ra nging fro m ha rdwa re to
middleware and applications, should head by describing the future of
information technology.
Research Themes
Cryptographic techniques using quantum information, post-quantum
cryptography● Quantum algorithms and quantum communication protocols●Quantum computer architecture, fault-tolerant quantum computer
technologies, quantum repeaters● Theoretical physics aimed at quantum information processing●

Bio-Medical Informatics Research Center

B i o - M e d i c a l I n f o r m a t i c s R e s e a rc h C e n t e r

Bio-Medical Informatics Research Center

Overview
The Bio - M edical Informatics Research Center (B M C) wasestablished in J uly, 2019 as a research organization in which
related N T T laboratories collaborate with the goal of creating
data - driven medicine using I CT and A I . T he B M C engages inbasic and applied research on AI analysis of medical and healthdata , genome informatio n a nd behavior informatio n , real-time
bio m o nito ring in d aily life , bio mim etic n a n o d evic es , a n d n ew
biocompatible materials. In addition, it promotes innovations inmedical and health fields in cooperation with partners at medical
institutes and Medical & Health Informatics Laboratories (M EILab), NTT Research Inc.
Research Themes
Personalized medicine by AI analysis of personal medical data (precision
medicine)●Cardiac modeling and rehabilitation activities supported by AI-telestethoscope and hitoe® ECG measurement●Lifestyle-related disease management based on noninvasive blood glucose
sensor and core body temperature sensor●Fabrication of implant materials and artificial neural networks thatcomplement biological functions●

12

Achievements in 2023

Nanostructure-implemented Semiconductor
Nanowire Lasers
Nanowire (NW) lasers are promising devices that can be integrated
into optical circuits. However, room-temperature continuous
operation of NW lasers has not been demonstrated yet as theinjected carriers cause heating problems. It is necessary toincorporate a cavity structure in the NW to improve the opticalconfinement and reduce the lasing threshold. Here, we establisheda technique to directly implement a nanocavity on a NW by using a
focused ion beam (FIB). Damage to the active layer caused by FIB
Ga ions was a critical issue, but we succeeded in suppressing thedamage by forming an alumina film as a hard mask.

M. Takiguchi, G. Zhang, S. Sasaki, K. Tateno, C. John, M. Ono, H. Sumikura, A. Shinya, and M. Notomi,
Nanotechnology 34, 135301 (2023).

(a)Nanostructure-implemented nanowire laser(b) Cross-sectional view of the nanowire(c) Lasing spectrum

Scaling of Errors in DigitizedCounterdiabatic Driving

1

InfidelityCounterdiabatic driving is a method of obtaining an adiabatic state
without requiring adiabatic conditions. It is a potential means ofovercoming a drawback of quantum adiabatic algorithms. A digital
implementation of counterdiabatic driving was recently reported. We
found that digitization errors of counterdiabatic driving show better
scaling than the conventional expectation. Our findings enhance
the usefulness of digitized counterdiabatic driving.

0.1

0.01
100
Trotter number

T. Hatomura, New J. Phys. 25, 103025 (2023).

Amount of digitization errors versus number of digitization steps. Better scaling (solidline) than conventional expectation (dashed line) appears for small numbers of steps.

Biomorphic Actuation with Light-driven On-chip
Hydrogel Actuators

R. Takahashi, A. Tanaka, and M. Yamaguchi, Adv. Funct. Mater. 33, 2300184 (2023).

(A)

(B)
ON

OFF

3D buckled state

Whole image

Light stimulation

2D flat state

Segmentation

Photo-responsivehydrogelFluorescence

0s

Contents

2s

Segmentation(After 1 cycle)

4s

Segmented point

1 mm

Whole image
Actuator

Reproduction of living organ-like motion
by controlling light stimulation

Peristalsis

Actuators using photoresponsive hydrogel can be used to smooththe movements of devices made of soft materials in a way thatmimics living organisms. The challenge has been to increase theresponse speed and displacement. In this study, we fabricated an
actuator with performance comparable to that of a living organ. The
actuator has a thin and porous design that increases the response
speed and an on-chip buckling mechanism that amplifies thedisplacement. With a luminal structure that closely resembles livingorgans, this actuator is capable of complex motions (segmentationand peristalsis) similar to those of the intestinal tract. We believethat this development will contribute to the creation of organ chips.

0s(Start scanning)

Peristalsis

Fluorescence

3s

9s

Transported

1 mm(A) Schematic illustration of behavior of light-driven on-chip hydrogel actuator(B) Demonstration of segmental movement (upper) and peristaltic movement (lower)
controlled by light stimulation

13

NTT Fellow

D e c e m b e r 31 , 2023

Shingo Tsukada

Hiroshi Yamaguchi

Masaya Notomi
Nanophotonics Center Project Manager

Research Subject

Research Subject

Research Subject

Medicine, Physiology, Biomedical Interface &Nano-mechanics in Semiconductors

Photon Manipulation in Photonic
Nanostructures

Akira Fujiwara

Hiroki Takesue

Data Analysis

Senior Distinguished Researcher

Koji Muraki

Quantum Science and Technology Laboratory
Executive Manager

Research Subject

Research Subject

Research Subject

Electron Correlation in Semiconductor
Nanostructures

Ultimate Electronics Using Semiconductor
Nanostructures

Quantum Communication Experiments in
Telecommunication Band
Coherent Ising Machine

Hideki Yamamoto

Shiro Saito

Yoshitaka Taniyasu

Multidisciplinary Materials Design and Science
Laboratory Executive Manager

Quantum Optical Physics Research Group
LeaderThin-Film Materials Research Group Leader
Low-Dimensional Nanomaterials Research Group Leader

Research Subject

Research Subject

Research Subject

Design and Thin-film Synthesis of Novel
Superconductors and Magnetic Materials with
Elucidation of the Underlying Physics

Quantum Information Technologies Based on
Superconducting Quantum Circuits

Research on Functional Materials for Green
Innovation

Distinguished Researcher

Norio Kumada
Koji Azuma

Katsuhiko Nishiguchi
Takahiro Inagaki

Imran Mahboob
Gento Yamahata

Haruki Sanada
Hajime Okamoto

Associate Distinguished
Researcher

Yuki K. Wakabayashi

14

Publication List

The total number of NTT Basic Research Laboratories papers published ininternational journals in 2023 is 69 with an average impact factor of 6.259.
The 2022 impact factor of those individual journals are shown in ( ).

PHYSICAL REVIEW APPLIED (4.6)

5

NEW JOURNAL OF PHYSICS (3.3)

5

APPLIED PHYSICS LETTERS (4)4PHYSICAL REVIEW B (3.7)

4

COMMUNICATIONS PHYSICS (5.5)

3

OPTICS EXPRESS (3.8)

3

PHYSICAL REVIEW A (2.9)

3

ADVANCED FUNCTIONAL MATERIALS (19)2

SCIENTIFIC REPORTS (4.6)

2

PHYSICAL REVIEW RESEARCH (4.2)

2

OPTICS LETTERS (3.6)

2

PHYSICAL REVIEW MATERIALS (3.4)

2

APPLIED PHYSICS EXPRESS (2.3)

2JAPANESE JOURNAL OF APPLIED PHYSICS (1.5)

2

SCIENCE (56.9)

1

REVIEWS OF MODERN PHYSICS (44)1

SCIENCE BULLETIN (18.9)

1

ACS NANO (17.1)

1

PHYSICAL REVIEW X (12.5)

1

NANO LETTERS (10.8)

1NANOSCALE HORIZONS (9.7)

1
1

2

3

4

Number of Presentations

Number of Patents

138

50

（39 Invited talks）

5

List of Award Winners
Support Center for Advanced Telecommunications Technology Research (SCAT) Chairman Award, 2022.
Research and Development of Quantum Key Distribution Over Optical Fiber

Toshimori Honjo

Electronics Society Activity Testimonial
Contribution as a Co-chair of the 12th QIT Steering Committee

Koji Azuma

The Young Scientist Award for an Excellent Article“Designing Superlattices of Cuprates and Ferrites for Superconductivity”ACS Applied Electronic Materials, 4 (2022) 2672

Ai Ikeda

The 53rd Young Scientist Presentation Award at The Japan Society of Applied Physics
MHz-repetition-rate Generation of 1.7-cycle Intense Pulses Using an 80W Yb:KGW Laser
Takuya Okamoto

High Performance Computing Infrastructure Consortium, 2023 HPCI Software Awards [Development Category Award] Encouragement AwardSALMON (Scalable Ab-initio Light-Matter simulator for Optics and Nanoscience)
Shunsuke Yamada, Yuta Hirokawa, Kenji Iida, Jun-ichi Iwata, Shinji Noda, Tomohito Otobe, Shunsuke Sato, Yasushi Shinohara, Takashi Takeuchi,
Mizuki Tani, Mitsuharu Uemoto, Kazuhiro Yabana, Atsushi Yamada

JSAP Fellow
Exploration of Novel Properties of Photonic Crystals and Application to Integrated Nanophotonics

Masaya Notomi

The 70th Spring Meeting of the Japan Society of Applied Physics Young Researcher Best Presentation Award
Biomimetic Actuation Leveraging on-chip Buckling Deformation of Photoresponsive Gels

Riku Takahashi

Young Scientist Award of the Physical Society of Japan
Pioneering Terahertz Spectroscopy Techniques for Investigating Ultrafast Local and Nonlocal Responses

Katsumasa Yoshioka

The Japan Society of Mechanical Engineers, Sports and Human Dynamics Division, Excellent Presentation Audience Award
Score Prediction Using Postural Tremor During Aiming in Archery

Takayuki Ogasawara

35th International Microprocesses and Nanotechnology Conference (MNC 2022) Most Impressive Presentation Award
Room-temperature Single-electron Sensor for AC Signals beyond an RC Time Constant 〜 Energy Transfer via a non-leakage DRAM in non-equilibrium 〜
Katsuhiko Nishiguchi, Akira Fujiwara, Kensaku Chida

35th International Microprocesses and Nanotechnology Conference (MNC 2022)

Most Impressive Poster

High-overtone Bulk Acoustic Resonator with Epitaxial AlN Layer Grown on n-SiC
Megumi Kurosu, Daiki Hatanaka, Ryuichi Ohta, Keiko Takase, Hiroshi Yamaguchi, Yoshitaka Taniyasu, Hajime Okamoto

IOP Trusted Reviewer Status
Takuya Hatomura