We are interested in nonequilibrium physics of quantum many-body systems and statistical mechanics. The aim is to realize a new order or new physical property by driving quantum systems out of equilibrium. At first sight, it sounds unlikely to happen because energy injected by an external drive would turn into heat, which would destroy all the interesting properties of quantum many-body systems that might emerge at low energies. However, contrary to our intuition, recent studies have found various possibilities such that novel states of matter that can never be realized in equilibrium do emerge out of equilibrium. We are trying to understand their mechanism and explore the frontier of nonequilibrium condensed matter physics.
・24/11/2023 We had a StatPhys seminar given by Prof. Hiroshi Shinaoka (Saitama University) with the title “Quantics Tensor Cross Interpolation for High-Resolution, Parsimonious Representations of Multivariate Functions in Physics and Beyond”.
・17/11/2023 We had a StatPhys seminar given by Mr. Kanta Masuki (University of Tokyo) with the title “Cavity QED control of quantum materials”.
・13-14/11/2023 We hosted the workshop “Frontiers of Nonequilibrium Solid States” at Hongo campus in the University of Tokyo.
・10/11/2023 We had a StatPhys seminar given by Prof. Kohei Kawabata (ISSP, University of Tokyo) with the title “Lieb-Schultz-Mattis Theorem in Open Quantum Systems”.
・08/11/2023 We had a seminar by Yuriko Baba (Complutense University of Madrid) with the title “Chern number tuning in QAH systems”.
・16-18/10/2023 Our group has joined the international conference “Trends in the Theory of Quantum Materials 2023” at Kashiwa. Takasan gave an invited talk.
・10/10/2023 We published review articles, “Higgs and Nambu-Goldstone modes in condensed matter physics” (N. Tsuji, I. Danshita, S. Tsuchiya, Encyclopedia of Condensed Matter Physics 2nd ed., Vol. 1, 174 (2024)), and “Floquet States” (N. Tsuji, Encyclopedia of Condensed Matter Physics 2nd ed., Vol. 1, 967 (2024)).
・20/09/2023 We launched a website for the workshop “Frontiers of nonequilibrium solid states” that will be held on Nov. 13-14th.
・16-19/09/2023 Tsuji, Takasan, Imai, Zhang, Ushihara, Nishimura, and Nagashima gave presentations at JPS Annual Meeting 2023.
・04/09/2023 Tsuji gave an invited talk at the workshop “Microscopic approach from pair correlation to pair condensation” at Osaka University, RCNP.
・21/08/2023 Tsuji gave an invited talk at the workshop “Frontiers of strongly correlated electron systems” at Nagoya University.
・07-11/08/2023 Tsuji, Takasan, Zhang, and Ushihara gave presentations at the International Conference on Statistical Physics (Statphys28).
・02/06/2023 Shohei Imai gave a talk, “Theory of attosecond dynamics of electrons in solids driven by optical electric fields”, at the StatPhys seminar.
・31/05/2023 Tsuji gave a seminar talk, “Nonlinear response in superconductors and beyond” at Max Planck Institute for Solid State Research (Stuttgart, Germany).
・20/04/2023 Tsuji wrote a book review of “Symmetry and topology of quantum many-body systems” written by Haruki Watanabe in Mathematical Sciences.
・03/04/2023 Shohei Imai joined our group as a project assistant professor. Keigo Takahashi, Ryosuke Hirakida, Raigo Nagashima, Taiga Nakamoto joined our group. Satoko Kimura joined our group as an assistant.
・31/03/2023 Tsuji gave an online seminar talk “Collective modes in superconductors: a new perspective from nonlinear terahertz responses” at IBS CCES (Seoul National University).
・17/02/2023 Our office has been renovated and new office furnitures are installed.
・08/02/2023 We published a paper, “Spin-polarized spatially indirect excitons in a topological insulator” (Mori et al., Nature 614, 249 (2023)).
・31/01/2023 We posted a review article “Floquet States” on arXiv:2301.12676.
・26/12/2022 Kazuaki Takasan gave a talk in Online Lecture for high school students.
・09/12/2022 We had a StatPhys seminar given by Dr. Kazuya Fujimoto (Tokyo Institute of Technology) with the title “Growth of particle-number fluctuations in one-dimensional quantum systems”.
・16/11/2022 Tsuji gave an invited talk at the international conference “Novel Quantum States in Condensed Matter 2022” at Kyoto University.
・01/11/2022 Tsuji gave an invited talk at the international conference “Trends in the Theory of Quantum Materials 2022” in ETH Zurich.
・26/10/2022 Our group has joined Newton Cafe.
・21/10/2022 We had a StatPhys seminar given by Dr. Tokiro Numasawa (ISSP, Univ. of Tokyo) with the title “SYK Lindbladian”.
・06/10/2022 Niklas Ziereis joined our group as a research student.
・20/09/2022 Kazuaki Takasan was accepted to JST PRESTO project “Quantum Cooperation between Materials and Information”.
・13/09/2022 Tsuji gave a talk at The JPS Autumn Meeting.
・22/06/2022 Tsuji gave a talk at JST FOREST Public Symposium.
・20/06/2022 Kazuaki Takasan gave a talk, “Activity-induced quantum phase transitions: A proposal for quantum active matter”, at the Statphys seminar.
・13/06/2022 Tsuji gave a talk at the 4th Bussei seminar.
・27-28/05/2022 We joined the graduate course guidance and the open lab event.
・21/04/2022 Our group has an open position for a project assistant professor. For details, see here. → The application has been closed.
・12/04/2022 Tsuji has received The Young Scientists’ Award by the Minister of Education, Culture, Sports, Science and Technology (MEXT) (School of Science HP, Department of Physics HP, RIKEN HP).
・01/04/2022 Kazuaki Takasan joined our group as an assistant professor. Hiromu Ushihara and Shunsuke Nishimura joined our group.
・01/04/2022 Tsuji was accepted to JST FOREST project, and the research project “Creation of condensed matter physics of high-energy superconductivity” has started.
・30/03/2022 We published a paper, “Optical response of the Leggett mode in multiband superconductors in the linear response regime” (Kamatani et al., Phys. Rev. B 105, 094520 (2022)).
・23/03/2022 Tsuji gave a talk at the meeting about phase transition dynamics at early universe.
・16/03/2022 Tsuji gave a talk at The JPS Annual Meeting.
・08/02/2022 Tsuji coauthored an article “Quantum Many-Body Physics of Open Systems in Ultracold Atoms” in Butsuri Gakkaishi.
・09/12/2021 Tsuji has been elected as The University of Tokyo Excellent Young Researcher. (Department of Physics HP)
・29/11/2021 We had a StatPhys seminar given by Dr. Sota Kitamura (Univ. of Tokyo) with the title “Nonreciprocal current response in the Landau-Zener problem”.
・25/11/2021 We posted a paper “Optical response of the Leggett mode in multiband superconductors in the linear response regime” on arXiv:2111.12318.
・09/11/2021 Our group has joined Newton Cafe.
・18/10/2021 We had a StatPhys seminar given by Dr. Yusuke Nomura (RIKEN CEMS) with the title “Quantum many-body problems and artificial neural networks”.
・01/10/2021 Huanyu Zhang joined our group.
・17/09/2021 Our group has an open position for an assistant professor. For details, see here. → The application has been closed.
・29/07/2021 We published a paper, “Collective Excitations and Nonequilibrium Phase Transition in Dissipative Fermionic Superfluids” (Yamamoto et al., Phys. Rev. Lett. 127, 055301 (2021)).
・13/07/2021 Tsuji gave a condensed-matter theory seminar at Osaka University.
・12-14/07/2021 Tsuji gave an intensive lecture “Recent developments of nonequilibrium physics in quantum many-body systems” at IPC, Graduate School of Science, Osaka University.
・28/06/2021 We had a StatPhys seminar given by Dr. Yuta Murakami (Tokyo Institute of Technology) with the title “Nonthermal orders in strongly correlated systems”.
・28-29/05/2021 We joined the graduate course guidance and the open lab event.
・26/04/2021 Tsuji joined the undergraduate cource guidance.
・20/04/2021 Tsuji gave a talk at the official seminar at Department of Physics.
・26/03/2021 We posted a paper “η Pairing of Light-Emitting Fermions: Nonequilibrium Pairing Mechanism at High Temperatures” on arXiv:2103.13624.
・12/03/2021 Tsuji gave a talk at The JPS Annual Meeting.
・03/03/2021 We posted a paper “Tachyonic and Plasma Instabilities of η-Pairing States Coupled to Electromagnetic Fields” on arXiv:2103.01547.
・05/02/2021 Our group has joined Newton Cafe.
・23/12/2020 Our group has joined Newton Cafe.
・21/10/2020 Tsuji gave a talk at StatPhys seminar at University of Tokyo.
・16/10/2020 Tsuji group has been launched.
Research introduction video
Kazuaki Takasan gave an introductory talk (in Japanese) in Online lecture for high school students.
Department of Physics, University of Tokyo
Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
E-mail: tsuji [at] phys.s.u-tokyo.ac.jp