Faculty Profiles - FUJIMOTO KAZUYA

写真a

FUJIMOTO KAZUYA

Organization

School of Science Assistant Professor

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Research Areas

Natural Science / Mathematical physics and fundamental theory of condensed matter physics
Natural Science / Semiconductors, optical properties of condensed matter and atomic physics

Education

Osaka City University

2013.4 - 2016.3

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Research History

Institute of Science Tokyo Assistant Professor

2024.10

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Tokyo Institute of Technology Assistant Professor

2022.4 - 2024.9

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Nagoya University Nagoya University

2019.4 - 2022.3

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The University of Tokyo Graduate School of Science

2016.4 - 2019.3

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Osaka City University

2014.4 - 2016.3

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Professional Memberships

THE PHYSICAL SOCIETY OF JAPAN

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Papers

Equation of State for Turbulence in the Gross-Pitaevskii Model Reviewed

Gevorg Martirosyan, Kazuya Fujimoto, Nir Navon

Physical Review Letters 136 ( 15 ) 2026.4

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Language：English Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

We report the numerical observation of a far-from-equilibrium equation of state (EOS) in the Gross-Pitaevskii (GP) model. We first show that the momentum distribution of the turbulent cascade is well described by wave-turbulent kinetic theory in the appropriate limits. Calculating the energy and particle fluxes Π ϵ ( k ) and Π N ( k ) , we show that the turbulent state possesses the hallmarks of a direct energy cascade. Building on this, we show that the GP model encodes a universal EOS in the form of a relationship between the turbulent cascade’s momentum distribution amplitude n 0 and the energy flux ε in the steady state. We find that in our regime of “mixed” turbulence—where both vortices and waves play a significant role— n 0 ∝ ε 0.67 ( 2 ) , a result that is not captured by any existing theory of turbulence but that agrees with a recent experimental measurement for large energy fluxes. Finally, we find that the concept of quasi-static thermodynamic processes between equilibrium states extends to far-from-equilibrium steady states.

DOI： 10.1103/1ppc-pl4k

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/1ppc-pl4k/fulltext
Quantum Transport in Interacting Spin Chains: Exact Derivation of the Tracy-Widom Distribution Reviewed

Kazuya Fujimoto, Tomohiro Sasamoto

Physical Review Letters 136 ( 8 ) 2026.2

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/lbl9-n9ws

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/lbl9-n9ws/fulltext
Path-integral formulation of bosonic Markovian open quantum dynamics with Monte Carlo stochastic trajectories using the Glauber–Sudarshan P, Wigner, and Husimi Q functions and hybrids Reviewed

Toma Yoneya, Kazuya Fujimoto, Yuki Kawaguchi

Annals of Physics 485 170325 - 170325 2026.2

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Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier BV

DOI： 10.1016/j.aop.2025.170325

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Path-integral formulation of truncated Wigner approximation for bosonic Markovian open quantum systems Reviewed

Toma Yoneya, Kazuya Fujimoto, Yuki Kawaguchi

Annals of Physics 479 170072 - 170072 2025.8

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Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier BV

DOI： 10.1016/j.aop.2025.170072

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Exact density profile in a tight-binding chain with dephasing noise Reviewed

Taiki Ishiyama, Kazuya Fujimoto, Tomohiro Sasamoto

Journal of Statistical Mechanics: Theory and Experiment 2025 ( 3 ) 033103 - 033103 2025.3

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Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

We theoretically investigate the many-body dynamics of a tight-binding chain with dephasing noise on an infinite interval. We obtain the exact solution of the average particle-density profile for the domain wall and the alternating initial conditions via the Bethe ansatz, analytically deriving the asymptotic expressions for the long-time dynamics. For the domain wall initial condition, we obtain the scaling form of the average density, elucidating that diffusive transport always emerges in the long-time dynamics if the strength of the dephasing, no matter how small, is positive. For the alternating initial condition, our exact solution leads to the fact that the average density displays oscillatory decay or overdamped decay depending on the strength of the dissipation. Furthermore, we demonstrate that the asymptotic forms approach those of the symmetric simple exclusion process, identifying corrections from it.

DOI： 10.1088/1742-5468/adba43

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Other Link： https://iopscience.iop.org/article/10.1088/1742-5468/adba43/pdf
Exact Solution of Bipartite Fluctuations in One-Dimensional Fermions Reviewed

Kazuya Fujimoto, Tomohiro Sasamoto

Physical Review Letters 134 ( 6 ) 2025.2

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/physrevlett.134.067101

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.134.067101/fulltext
Random Matrix Statistics in Propagating Correlation Fronts of Fermions Reviewed

Kazuya Fujimoto, Tomohiro Sasamoto

Physical Review Letters 132 ( 8 ) 2024.2

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/physrevlett.132.087101

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.132.087101/fulltext
Designing nontrivial one-dimensional Floquet topological phases using a spin-1/2 double-kicked rotor Reviewed

Yusuke Koyama, Kazuya Fujimoto, Shuta Nakajima, Yuki Kawaguchi

Physical Review Research 5 ( 4 ) 2023.11

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Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/physrevresearch.5.043167

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.5.043167/fulltext
Impact of Dissipation on Universal Fluctuation Dynamics in Open Quantum Systems Reviewed

Kazuya Fujimoto, Ryusuke Hamazaki, Yuki Kawaguchi

Physical Review Letters 129 ( 11 ) 2022.9

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/physrevlett.129.110403

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.129.110403/fulltext
Spin-wave growth via Shapiro resonances in a spinor Bose-Einstein condensate Reviewed

Yuya Imaeda, Kazuya Fujimoto, Yuki Kawaguchi

Physical Review Research 3 ( 4 ) 2021.10

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Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/physrevresearch.3.043090

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.3.043090/fulltext
Dynamical Scaling of Surface Roughness and Entanglement Entropy in Disordered Fermion Models Reviewed

Kazuya Fujimoto, Ryusuke Hamazaki, Yuki Kawaguchi

Physical Review Letters 127 ( 9 ) 2021.8

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/physrevlett.127.090601

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.127.090601/fulltext
Magnetic soliton: From two to three components with SO(3) symmetry Reviewed

Xiao Chai, Di Lao, Kazuya Fujimoto, Chandra Raman

Physical Review Research 3 ( 1 ) 2021.1

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Language：English Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/physrevresearch.3.l012003

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.3.L012003/fulltext
Magnetic Solitons in a Spin-1 Bose-Einstein Condensate Reviewed

X. Chai, D. Lao, Kazuya Fujimoto, Ryusuke Hamazaki, Masahito Ueda, C. Raman

Physical Review Letters 125 ( 3 ) 2020.7

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Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/physrevlett.125.030402

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.125.030402/fulltext
Family-Vicsek Scaling of Roughness Growth in a Strongly Interacting Bose Gas Reviewed

Kazuya Fujimoto, Ryusuke Hamazaki, Yuki Kawaguchi

Physical Review Letters 124 ( 21 ) 2020.5

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/physrevlett.124.210604

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.124.210604/fulltext
Scale-invariant relaxation dynamics in two-component Bose-Einstein condensates with large particle-number imbalance Reviewed

Kazuya Fujimoto, Kazunori Haneda, Kazue Kudo, Yuki Kawaguchi

Physical Review A 101 023608 2020.2

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

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Floquet Spinor Bose Gases Reviewed

Kazuya Fujimoto, Shun Uchino

Phys. Rev. Research 1, 033132 2019.11

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Synthetic dissipation and cascade fluxes in a turbulent quantum gas Reviewed

Nir Navon, Christoph Eigen, Jinyi Zhang, Raphael Lopes, Alexander L. Gaunt, Kazuya Fujimoto, Makoto Tsubota, Robert P. Smith, Zoran Hadzibabic

Science 366 ( 6463 ) 382 - 385 2019.10

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Authorship：Corresponding author Publishing type：Research paper (scientific journal) Publisher：American Association for the Advancement of Science (AAAS)

Scale-invariant fluxes are the defining property of turbulent cascades, but their direct measurement is a challenging experimental problem. Here we perform such a measurement for a direct energy cascade in a turbulent quantum gas. Using a time-periodic force, we inject energy at a large length scale and generate a cascade in a uniformly trapped three-dimensional Bose gas. The adjustable trap depth provides a high-momentum cutoff <italic>k</italic>_D, which realizes a synthetic dissipation scale. This gives us direct access to the particle flux across a momentum shell of radius <italic>k</italic>_D, and the tunability of <italic>k</italic>_D allows for a clear demonstration of the zeroth law of turbulence. Moreover, our time-resolved measurements give unique access to the pre–steady-state dynamics, when the cascade front propagates in momentum space.

DOI： 10.1126/science.aau6103

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Flemish Strings of Magnetic Solitons and a Nonthermal Fixed Point in a One-Dimensional Antiferromagnetic Spin-1 Bose Gas Reviewed

Kazuya Fujimoto, Ryusuke Hamazaki, Masahito Ueda

Physical Review Letters 122 ( 17 ) 2019.5

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal)

DOI： 10.1103/physrevlett.122.173001

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.122.173001/fulltext
Operator Noncommutativity and Irreversibility in Quantum Chaos

Ryusuke Hamazaki, Kazuya Fujimoto, Masahito Ueda

arXiv:1807.02360 2018.7

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Unconventional Universality Class of One-Dimensional Isolated Coarsening Dynamics in a Spinor Bose Gas Reviewed

Kazuya Fujimoto, Ryusuke Hamazaki, Masahito Ueda

Physical Review Letters 120 ( 7 ) 2018.2

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal)

DOI： 10.1103/physrevlett.120.073002

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.120.073002/fulltext
Numerical Studies of Quantum Turbulence Reviewed

Makoto Tsubota, Kazuya Fujimoto, Satoshi Yui

JOURNAL OF LOW TEMPERATURE PHYSICS 188 ( 5-6 ) 119 - 189 2017.9

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Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1007/s10909-017-1789-8

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Bogoliubov-wave turbulence in Bose-Einstein condensates (vol 91, 053620, 2015) Reviewed

Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW A 93 ( 3 ) 039901 2016.3

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.93.039901

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Direct and inverse cascades of spin-wave turbulence in spin-1 ferromagnetic spinor Bose-Einstein condensates Reviewed

Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW A 93 ( 3 ) 033620 2016.3

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.93.033620

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Logarithmic velocity profile of quantum turbulence of superfluid He-4 Reviewed

Satoshi Yui, Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW B 92 ( 22 ) 224513 2015.12

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Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevB.92.224513

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Bogoliubov-wave turbulence in Bose-Einstein condensates Reviewed

Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW A 91 ( 5 ) 053620 2015.5

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.91.053620

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Spin-superflow turbulence in spin-1 ferromagnetic spinor Bose-Einstein condensates Reviewed

Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW A 90 ( 1 ) 013629 2014.7

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.90.013629

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Spin turbulence with small spin magnitude in spin-1 spinor Bose-Einstein condensates Reviewed

Kazuya Fujimoto, Makoto Tsubota

Physical Review A 88 ( 6 ) 2013.12

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/physreva.88.063628

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevA.88.063628/fulltext
Spin-glass-like behavior in the spin turbulence of spinor Bose-Einstein condensates Reviewed

Makoto Tsubota, Yusuke Aoki, Kazuya Fujimoto

PHYSICAL REVIEW A 88 ( 6 ) 061601(R) 2013.12

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Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.88.061601

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Spin turbulence in a trapped spin-1 spinor Bose-Einstein condensate Reviewed

Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW A 85 ( 5 ) 053641 2012.5

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.85.053641

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Counterflow instability and turbulence in a spin-1 spinor Bose-Einstein condensate Reviewed

Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW A 85 ( 3 ) 033642 2012.3

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.85.033642

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Nonlinear dynamics in a trapped atomic Bose-Einstein condensate induced by an oscillating Gaussian potential Reviewed

Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW A 83 ( 5 ) 053609 2011.5

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.83.053609

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Synergy dynamics of vortices and solitons in an atomic Bose-Einstein condensate excited by an oscillating potential Reviewed

Kazuya Fujimoto, Makoto Tsubota

PHYSICAL REVIEW A 82 ( 4 ) 043611 2010.10

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevA.82.043611

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MISC

孤立量子系の粒子数揺らぎに現れる界面粗さスケーリング Invited

藤本和也, 濱崎立資, 川口由紀

日本物理学会誌、最近の研究から 76 ( 8 ) 517 - 522 2021.8

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Authorship：Lead author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal)

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Universal Relaxation in Quantum Systems Invited

Kazuya Fujimoto, Masahito Ueda

Emerging Frontiers in Nonlinear Science 111 - 130 2020

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Authorship：Lead author Language：English Publisher：Springer International Publishing

DOI： 10.1007/978-3-030-44992-6_5

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Awards

第16回日本物理学会若手奨励賞（2022年）

2022.3

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Poster preview award (Fourth Annual Meeting of Topological Material Science)

2019.1

藤本和也

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第34回井上研究奨励賞

2018.2

藤本和也

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Poster preview award (Third Annual Meeting of Topological Material Science)

2017.5

藤本和也

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日本物理学会2015年秋季大会領域1学生プレゼンテーション賞

2016.3

藤本和也

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Research Projects

量子情報と界面粗さ成長の視点から解明する量子ダイナミクスの普遍性

Grant number：23K13029 2023.4 - 2028.3

日本学術振興会科学研究費助成事業若手研究若手研究

藤本和也

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Grant amount：\4810000 （ Direct Cost: \3700000 、 Indirect Cost：\1110000 ）

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開放量子系における非平衡ダイナミクスの普遍的性質の理論研究

2020.10 - 2021.3

木下記念事業団木下基礎科学研究基金

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Authorship：Principal investigator

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Visualizing the phase separation of a dual-BEC for verifying the dynamical scaling hypothesis

Grant number：20H01843 2020.4 - 2023.3

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B) Grant-in-Aid for Scientific Research (B)

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Authorship：Coinvestigator(s)

Grant amount：\17810000 （ Direct Cost: \13700000 、 Indirect Cost：\4110000 ）

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Universality of thermalization dynamics in cold atomic gases

Grant number：19K14628 2019.4 - 2023.3

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Early-Career Scientists Grant-in-Aid for Early-Career Scientists

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Authorship：Principal investigator

Grant amount：\4030000 （ Direct Cost: \3100000 、 Indirect Cost：\930000 ）

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Topological quantum phenomena in atomic Bose-Einstein condensates

Grant number：19H01824 2019.4 - 2023.3

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B) Grant-in-Aid for Scientific Research (B)

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Authorship：Coinvestigator(s)

Grant amount：\15210000 （ Direct Cost: \11700000 、 Indirect Cost：\3510000 ）

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極低温冷却原子気体における次元依存性を持つ非平衡ダイナミクスの理論的研究

2016.4 - 2019.3

日本学術振興会特別研究員奨励費(PD)

藤本和也

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Authorship：Principal investigator Grant type：Competitive

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スピノール・ボース・アインシュタイン凝縮体におけるスピン乱流の理論的研究

2014.4 - 2016.3

日本学術振興会特別研究員奨励費(DC2)

藤本和也

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Authorship：Principal investigator Grant type：Competitive

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