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

.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

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

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

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

Reference:

FIG. 2. Diffusion constant obtained from various measurement
method compared with nanoscale correlation spectroscopy

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

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).

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).

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.

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.

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).

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
Oyama K, Mizuno A, Shintani SA, Itoh H, Serizawa T, Fukuda N, et al. Microscopic heat pulses induce1.
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).

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

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%.

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

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

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.

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).

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

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

12