News
53 news in 2025
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2025-04-17
Paper of the WeekWeek 3, April 2025
Title: Cohomology ring of unitary $N=(2,2)$ full vertex algebra and mirror symmetry Author: Yuto Moriwaki arXiv: http://arxiv.org/abs/2504.09919v1
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2025-04-17
Award
Masazumi Honda received "Commendation for Science and Technology: the Young Scientists' Award"
Our colleague Masazumi Honda received "Commendation for Science and Technology: the Young Scientists' Award" in recognition of his outstanding research achievements in the theoretical studies of strong-coupling dynamics in quantum field theories. Congratulations to Masazumi !
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2025-04-14
Research News
RIKEN Research: When it comes to modeling, even unmeasurable data tells us something
Mathematical models for predicting how cancer tumors in mice grow over time can give distorted results if unmeasurable data is ignored, a team that includes two RIKEN researchers has shown1. This finding has important implications when applying mathematical models to medicine. A self-confessed data geek, Catherine Beauchemin of the RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) specializes in applying the power of math to everything from viruses to supernovae. “I love trying to figure out what data are telling us,” she says. Seeking new insights into cancer mechanisms, Beauchemin’s team used mathematical models to analyze previously published data of tumor-size measurements over time for ten mice. To read more, please visit the related link.
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2025-04-14
Research News
RIKEN Research: Refined test could improve Parkinson’s disease diagnosis
A team that includes a RIKEN researcher has refined a lab test for measuring protein aggregate levels in samples from patients with certain neurodegenerative diseases1. This has the potential to improve diagnosis and drug development for these diseases. Synucleinopathies are neurodegenerative diseases such as Parkinson’s disease and dementia with Lewy bodies. They are associated with the accumulation of aggregates of misfolded alpha-synuclein proteins in the brain and spinal cord. “When a misfolded alpha-synuclein protein in a neuron encounters one of its properly folded counterparts, it causes it to become misfolded,” says Catherine Beauchemin of the RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences. “The two misfolded alpha-synuclein proteins stick together and cause other normal alpha-synuclein to misfold and aggregate.” To read more, please visit the related link.
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2025-04-14
Press ReleaseDemonstration of Quantum Information Delocalization in a Periodically Driven System
A collaborative research team, including Visiting Scientists Yuta Kikuchi and Tomoya Hayata, has demonstrated that a scrambled state—in which quantum information becomes delocalized—can be prepared using a quantum circuit that simulates a periodically driven system. This was achieved with an ion-trap quantum computer. Scrambled states possess characteristics that are expected to be beneficial for quantum information recovery and many-body quantum system computations. This achievement represents an early-stage application of quantum computing in an academic research domain where physical phenomena and quantum information intersect, and is anticipated to contribute to the promotion of quantum computing utilization in Japan. In this study, the research team confirmed that a scrambled state—previously typically discussed using random quantum circuits—can also be prepared using periodically driven quantum circuits. This was validated through a combination of practical implementation on a high-fidelity quantum computer, appropriate error mitigation techniques, and theoretical analysis. For further details, please refer to the press release available via the related link.
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2025-04-14
Research News
RIKEN NEWS: Exploring Critical Magnetic Transport Phenomena with a Quantum Simulator
An interview with Yuta Sekino (Postdoctoral Researcher, iTHEMS) has been featured in Research Highlights, part of the "Close-up RIKEN 2025" series on RIKEN’s research introduction page. It has also been published in SPRING 2025 issue of RIKEN’s public relations magazine, RIKEN NEWS. Postdoctoral Researcher Yuta Sekino is theoretically investigating the behavior of "many-particle systems," which are collections of particles. He devised a new model that captures the flow of magnetism by confining individual atoms in an ultrafine lattice (optical lattice) created with lasers. Through theoretical calculations based on this model, he discovered a mysterious magnetic transport phenomenon. For more details, please see the related link.
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2025-04-10
Paper of the WeekWeek 2, April 2025
Title: Irrationality of the reciprocal sum of doubly exponential sequences Author: Junnosuke Koizumi arXiv: http://arxiv.org/abs/2504.05933v1 Title: Re-evaluation of the deuteron-deuteron thermonuclear reaction rates in metallic deuterium plasma Author: Faisal Etminan arXiv: http://arxiv.org/abs/2504.05003v1 Title: Thermonuclear superburst of MAXI J1752$-$457 observed with NinjaSat and MAXI Author: Amira Aoyama, Teruaki Enoto, Takuya Takahashi, Sota Watanabe, Tomoshi Takeda, Wataru Iwakiri, Kaede Yamasaki, Satoko Iwata, Naoyuki Ota, Arata Jujo, Toru Tamagawa, Tatehiro Mihara, Chin-Ping Hu, Akira Dohi, Nobuya Nishimura, Motoko Serino, Motoki Nakajima, Takao Kitaguchi, Yo Kato, Nobuyuki Kawai arXiv: http://arxiv.org/abs/2504.04352v1 Title: Finite-Temperature Perturbation Theory of Rotating Scalar Fields Author: Ryo Kuboniwa, Kazuya Mameda arXiv: http://arxiv.org/abs/2504.04712v1 Title: A satellite formula for real Seiberg-Witten Floer homotopy types Author: Jin Miyazawa, JungHwan Park, Masaki Taniguchi arXiv: http://arxiv.org/abs/2504.03270v1
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2025-04-09
Hot Topic
Greeting from the Director, Satoshi Iso
This April, iTHEMS entered a new phase with a renewed and expanded structure. While we continue to grow and evolve, the spirit of iTHEMS remains unchanged.
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2025-04-08
Research NewsRIKEN NEWS: Unraveling the Evolutionary Mechanisms of Cooperative Behavior Using Fugaku
An interview article with Yohsuke Murase (Senior Research Scientist) has been featured in Research Highlights, part of the "Close-up RIKEN 2025" series on RIKEN’s research introduction page. It has also been published in SPRING 2025 issue of RIKEN’s public relations magazine, RIKEN NEWS. We humans, often described as social animals, engage in "cooperative behavior"—working together and helping one another. Focusing on the key role played by "reputation," Dr. Yohsuke Murase and an international research team analyzed the dynamics of this information using the supercomputer Fugaku. Their findings revealed the evolutionary path of humanity, shaped by cooperative behavior. For more details, please refer to the related links.
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2025-04-08
Hot Topic
iTHEMS Starter Meeting for FY 2025 on April 4, 2025
On Friday, April 4, 2025, the annual iTHEMS Starter Meeting was held at 12:30 PM in Suzuki Umetaro Hall. Unlike the regular Coffee Meetings that take place every Friday at the same time, the Starter Meeting marks the beginning of the academic year and serves as a special occasion to introduce new members, allow existing members to reintroduce themselves, and share the outlook for the year ahead. This year’s meeting was held on a larger scale than usual to commemorate a major organizational milestone—the transformation of iTHEMS from a program into the newly established RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences. The meeting opened with a commemorative talk by Tetsuo Hatsuda, former Program Director, who reflected on the history of interdisciplinary mathematical science research at RIKEN, beginning with the iTHES program and leading up to the evolution of iTHEMS. He also expressed heartfelt appreciation for the contributions of former Deputy Program Directors Takashi Tsuboi and Takemasa Miyoshi. Following his talk, the new Center Director, Satoshi Iso, provided an overview of the structure and vision for the newly reorganized iTHEMS, including the establishment of new research units and teams designed to further expand and deepen the center’s interdisciplinary mission. Flower bouquets were then presented to Hatsuda-san and Tsuboi-san as a gesture of gratitude, while Miyoshi-san, who was absent, was also acknowledged for his contributions. After a brief intermission, Tsukasa Tada, Deputy Director, introduced the newly adopted iTHEMS Code of Conduct. He emphasized its core principles—mutual respect, scientific integrity, inclusivity, and responsibility—and explained how the Code reflects the ethical foundation that each member is encouraged to uphold and shape as the community evolves. This was followed by a series of one-minute self-introductions by all members, each using a single slide, continuing the tradition of fostering familiarity and collaboration across disciplines. The meeting concluded slightly before 5:00 PM, after which participants returned to the Main Research Building to attend a reception in the open space on the third floor. The reception provided an opportunity for further discussion and networking among iTHEMS members and affiliated researchers, marking a warm and promising start to the new academic year under the expanded vision of the iTHEMS Center.
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2025-04-08
Hot Topic
Takashi Tsuboi Appointed Honorary Research Fellow at RIKEN
The former Deputy Program Director of iTHEMS, Takashi Tsuboi, has been appointed "Honorary Research Fellow" at RIKEN by President Makoto Gonokami, effective April 1, 2025.This honor recognizes Takashi’s many years of distinguished service as Deputy Program Director of iTHEMS (FY2017–FY2024), as well as his outstanding achievements and dedicated contributions. He will continue to support iTHEMS as a Senior Visiting Scientist. Congratulations, Takashi!
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2025-04-07
Award
Yan Lyu received FY2024 RIKEN Excellent Achievement Award (RIKEN BAIHO Award 理研梅峰賞)
Our colleague Yan Lyu received the FY2024 RIKEN Excellent Achievement Award (RIKEN BAIHO Award) on March 28, 2025, in recognition of his outstanding work on “Elucidation of Genuine Tetraquarks Based on Lattice Quantum Chromodynamics.” The photo was taken on April 4, 2025, on the way to Suzuki Umetaro Hall at the Wako campus. Congratulations, Yan!
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2025-04-07
Award
Kyosuke Adachi received FY2024 RIKEN Research and Technology Incentive Award (RIKEN OHBU Award 理研桜舞賞)
Our colleague Kyosuke Adachi received the FY2024 RIKEN Research and Technology Incentive Award (RIKEN OHBU Award) on March 28, 2025, in recognition of his outstanding work on “Unveiling the Rules of Amino Acid Sequences Governing Protein Condensation.” The photo was taken on April 4, 2025, on the way to Suzuki Umetaro Hall at the Wako campus. Congratulations, Kyosuke!
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2025-04-03
Person of the Week
Self-introduction: Erik Loetstedt
I have a PhD in theoretical physics from Heidelberg University and have worked at the Max Planck Institute for Nuclear Physics, Missouri University of Science and Technology and The University of Tokyo before coming to RIKEN. I am interested in time-dependent problems in quantum mechanics, in particular strong field-molecule interaction. I am also interested in the simulation of quantum dynamics of molecules by quantum computers.
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2025-04-03
Paper of the WeekWeek 1, April 2025
Title: Higgs-Modular Inflation Author: Shuntaro Aoki, Hajime Otsuka, Ryota Yanagita arXiv: http://arxiv.org/abs/2504.01622v1 Title: The untangling number of 3-periodic tangles Author: Toky Andriamanalina, Sonia Mahmoudi, Myfanwy E. Evans arXiv: http://arxiv.org/abs/2504.01747v1 Title: Universality of Rényi Entropy in Conformal Field Theory Author: Yuya Kusuki, Hirosi Ooguri, Sridip Pal arXiv: http://arxiv.org/abs/2503.24353v1 Title: Unstable chords and destructive resonant excitation of black hole quasinormal modes Author: Naritaka Oshita, Emanuele Berti, Vitor Cardoso arXiv: http://arxiv.org/abs/2503.21276v1 Title: Non-perturbative formulation of resonances in quantum mechanics based on exact WKB method Author: Okuto Morikawa, Shoya Ogawa arXiv: http://arxiv.org/abs/2503.18741v2 Title: A Promising Method for Strongly Correlated Electrons in Two Dimensions: Gutzwiller-Guided Density Matrix Renormalization Group Author: Hui-Ke Jin, Rong-Yang Sun, Hong-Hao Tu, Yi Zhou arXiv: http://arxiv.org/abs/2503.18374v1 Title: Effective field theory for weakly bound two-neutron halo nuclei: corrections from neutron-neutron effective range Author: Davi B. Costa, Masaru Hongo, Dam Thanh Son arXiv: http://arxiv.org/abs/2503.18519v1 Title: Path to an exact WKB analysis of black hole quasinormal modes Author: Taiga Miyachi, Ryo Namba, Hidetoshi Omiya, Naritaka Oshita arXiv: http://arxiv.org/abs/2503.17245v1 Title: Observation of Two Cascading Screening Processes in an Iron-based Superconductor Author: Ming-Hua Chang, Steffen Backes, Donghui Lu, Nicolas Gauthier, Makoto Hashimoto, Guan-Yu Chen, Hai-Hu Wen, Sung-Kwan Mo, Zhi-Xun Shen, Roser Valenti, Heike Pfau arXiv: http://arxiv.org/abs/2503.06314v1 Title: Monte Carlo study on Heisenberg model with local dipolar interaction Author: Etsuko Itou, Akira Matsumoto, Yu Nakayama, Toshiki Onagi arXiv: http://arxiv.org/abs/2503.15874v2
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2025-04-01
Hot Topic
Farewell message from Daiki Kumakura
Our colleague, Daiki Kumakura, joins R&D Division at Daiichi Sankyo Co. as Translational Scientist after receiving PhD last week from Hokkaido University. We wish him the best of luck in this new endeavor. Here is a message from Daiki: I joined iTHEMS as a Junior Research Associate (JRA) in April 2022, and since then I have been fortunate to experience a wealth of opportunities and engaging discussions that go far beyond what I encountered at university. When I started as a JRA, I set myself the dual goals of advancing both research and education. In research, I pursued mathematical and computational analyses with a focus on microbial themes. In education, I established a Young Researchers in Mathematical Biology group for students and organized a summer school. Additionally, I participated in public outreach by designing a “one poster per family” project, and through appearances on FM radio and our university’s YouTube channel, I helped spread the excitement of mathematical science and the unique identity of iTHEMS to students throughout Japan. I am deeply grateful to the many individuals at iTHEMS whose support made all of these endeavors possible. Thank you from the bottom of my heart. Starting in April 2025, I will be embarking on a new chapter as a Translational Scientist at Daiichi Sankyo Co., Ltd. In this role, I will analyze and interpret clinical trial data across various disease areas, including cancer, with the aim of enabling faster and more appropriate drug prescriptions for patients. I look forward to applying the invaluable experiences I gained at iTHEMS to establish a strong position for mathematical science in industrial applications. My career has flourished thanks to iTHEMS, and I sincerely wish for the continued growth and success of the iTHEMS community. I hope to maintain close ties with all of you in the future. Thank you very much for everything.
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2025-03-28
Book
Exploring Nuclear and Hadron Physics
Author: Tetsuo Hatsuda et al. Language: Japanese Release date: February, 2025
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2025-03-27
Book
The Story of the "Discovery" of Numbers
Author: Hiroyasu Miyazaki Language: Japanese Release date: March 25, 2025
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2025-03-26
Seminar Report
A Century of Quantum Mechanics by Gordon Baym on March 24, 2025
On March 24, Professor Gordon Baym gave a joint seminar hosted by the Department of Physics at the University of Tokyo and RIKEN iTHEMS, held at the Hongo campus of the University of Tokyo. His talk focused on the history of quantum mechanics, tracing its development and highlighting the contributions of key figures such as Max Planck, Albert Einstein, Niels Bohr, and Werner Heisenberg. He also discussed the profound impact of quantum mechanics on modern technology, particularly its role in the invention of the transistor and the cellphone. In addition, Professor Baym offered inspiring insights into the importance of phase information and the concept of the quantized photon. The seminar drew more than 100 attendees, including participants via Zoom, and concluded with a lively and engaging Q&A session. Reported by Tetsuo Hatsuda
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2025-03-24
Hot Topic
Farewell message from Akihisa Yamamoto
Our colleague, Akihosa Yamamoto, will be joining Department of Mechanical Systems Engineering, Faculty of Systems Design at Tokyo Metropolitan University as an Associate Professor starting April 1st, 2025. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Akihisa: I joined RIKEN iTHEMS as a research scientist in April 2024. Although it has only been a year, I truly enjoyed my time here. I have encountered many exciting and diverse research topics that have significantly expanded my scientific horizons and thoroughly enjoyed attending seminars across various fields. Due to the great diversity and high quality of the presentations, it has not always been easy to grasp the key take-home messages and formulate relevant questions. Nonetheless, I have always enjoyed the opportunity to immerse myself in these stimulating discussions. I am also very grateful for the positive atmosphere of iTHEMS, fostered by talented and considerate colleagues. It has been a great pleasure to be a part of this fantastic institute, and I sincerely thank the Program Director Hatsuda-san and every member of iTHEMS including all the assistants for collectively maintaining such a supportive environment. I will be appointed as an Associate Professor in the Biomechanical Engineering Area in the Department of Mechanical Systems Engineering, Faculty of Systems Design at Tokyo Metropolitan University on April 1st, 2025. I plan to continue my exploration of the mechanistic understanding of homeostasis and the dynamics of living systems. I am sure that the scientific perspective and thought processes I have developed during my time at iTHEMS will remain with me throughout my scientific career. I sincerely wish for the continuous and even greater success of iTHEMS, and I look forward to staying in touch with iTHEMS members.
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2025-03-23
Hot Topic
Farewell message from Rongyang Sun
Our colleague, Rongyang Sun, will be joining Department of Physics and Astronomy, California State University Northridge, as a postdoctoral researcher, starting April 2025. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Rongyang: I joined iTHEMS in April 2023 as part of RIKEN Quantum, and you may not even meet me on campus as my base is at R-CCS in Kobe. Although my time in iTHEMS has been short, formally only half a year, and I participated in the events remotely most of the time, I learned so much, far more than I expected, from this active research institute, which owns the best diversity and productivity. I would like to thank all the members of iTHEMS, including the directors, researchers, and assistants. Thank you for giving me such a unique experience in my research career! While I am moving to the US, a physically very far away place, I will continue to follow the development of iTHEMS and share in its success. Starting in April 2025, iTHEMS will be upgraded to a research center. I sincerely wish all the members and the institute greater success in this new era!
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2025-03-20
Paper of the WeekWeek 4, March 2025
Title: Pair Correlation Conjecture for the zeros of the Riemann zeta-function I: simple and critical zeros Author: Daniel Alan Goldston, Junghun Lee, Jordan Schettler, Ade Irma Suriajaya arXiv: http://arxiv.org/abs/2503.15449v1 Title: Frustration-free free fermions Author: Seishiro Ono, Rintaro Masaoka, Haruki Watanabe, Hoi Chun Po arXiv: http://arxiv.org/abs/2503.14312v1 Title: Stable homotopy theory of invertible gapped quantum spin systems I: Kitaev's $Ω$-spectrum Author: Yosuke Kubota arXiv: http://arxiv.org/abs/2503.12618v1 Title: Frustration-free free fermions and beyond Author: Rintaro Masaoka, Seishiro Ono, Hoi Chun Po, Haruki Watanabe arXiv: http://arxiv.org/abs/2503.12879v1 Title: Modular-invariant random matrix theory and AdS${}_3$ wormholes Author: Jan Boruch, Gabriele Di Ubaldo, Felix M. Haehl, Eric Perlmutter, Moshe Rozali arXiv: http://arxiv.org/abs/2503.00101v1
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2025-03-18
Hot Topic
Farewell message from Steffen Backes
Our colleague, Steffen Backes, will be joining the RIKEN TRIP Research DX Team as an Expert Technician, starting April 1, 2025. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Steffen: I joined iTHEMS and RIKEN in August 2023, so only about 1.5 years ago, but this time had a lasting impression on my personal life and scientific career. It is hard to overstate how much I enjoyed being part of iTHEMS, as it has been an incredibly enjoyable and rewarding time. Being able to meet so many knowledgeable and kind people from different fields and parts of the world, and coming up with new and unconventional ideas due to different backgrounds, was truly amazing. I am very grateful for having been accepted to iTHEMS, which I think is a very special and outstanding place due to this diversity and scientific freedom, that is hard to be found elsewhere. In FY2025 (April 1st) I will change to an Expert Technician position in the RIKEN TRIP Research DX Team, Wako Campus, so I will still stay close to iTHEMS! As far as time allows, I will make sure to drop by and say hello :) Thank you everyone for this great time, and let's meet again soon!
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2025-03-13
Paper of the WeekWeek 3, March 2025
Title: Gyromagnetic Angular Momentum Interconversion in Neutron Stars Author: Hiroshi Funaki, Yuta Sekino, Hiroyuki Tajima, Shota Kisaka, Nobutoshi Yasutake, Mamoru Matsuo arXiv: http://arxiv.org/abs/2503.06068v2 Title: Quartet correlations near the surface of $ N = Z $ nuclei Author: Yixin Guo, Tomoya Naito, Hiroyuki Tajima, Haozhao Liang arXiv: http://arxiv.org/abs/2503.07051v1 Title: Landscape computations for the edge of chaos in nonlinear dynamical systems Author: Motoki Nakata, Masaaki Imaizumi arXiv: http://arxiv.org/abs/2503.06393v1 Title: A diagrammatic approach to the Rasmussen invariant via tangles and cobordisms Author: Taketo Sano arXiv: http://arxiv.org/abs/2503.05414v1 Title: Mirror-skin thickness: A possible observable sensitive to the charge symmetry breaking energy density functional Author: Tomoya Naito, Yuto Hijikata, Juzo Zenihiro, Gianluca Colò, Hiroyuki Sagawa arXiv: http://arxiv.org/abs/2503.05147v1
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2025-03-12
Hot Topic
Farewell message from Jizhou Li
Our colleague, Jizhou Li, will be joining Professor Akira Shudo's group in the Department of Physics at Tokyo Metropolitan University as a postdoctoral researcher, starting April 1, 2025. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Jizhou: As I move on to my next position at Tokyo Metropolitan University, I just wanted to say a big thank you to all of you. I’ve really enjoyed the discussions, collaborations, and all the insightful talks at iTHEMS. The biology seminars and coffee meetings, in particular, have been a fantastic learning experience for me. Luckily, since I live just 1 km from RIKEN, I’m not going too far! I still plan to drop by for the biology seminar every Thursday, so I’m looking forward to more chats and discussions with you all. Thanks again, and see you around!
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2025-03-12
Award
iTHEMS received the "RIKEN Diversity Innitiative Award 2024"
On March 7, 2025, iTHEMS was honored with the "RIKEN Diversity Promotion Award 2024." This marks the second consecutive recognition, following our receipt of the same award in 2023. The award acknowledges our collaborative efforts with Nara Women's University, including lectures and a visiting program since 2020, as a forward-thinking initiative to promote the active participation of women in science. A heartfelt thank you to everyone who contributed to making this initiative a success!
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2025-03-10
Award
Tomoya Naito received the “PCM2025 Jury Prize”
Our colleague Tomoya Naito (Special Postdoctoral Researcher, iTHEMS) has received the “PCM2025 Jury Prize’” of the "Single-particle and collective motions from nuclear many-body correlation (PCM2025)” symposium. The outstanding presentation poster is entitled “Isospin symmetry breaking energy density functional based on quantum chromodynamics”. Congratulations, Tomoya!
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2025-03-06
Research News
Review on Physics-Driven Learning for Inverse Problems Published in Nature Reviews Physics
Nature Reviews Physics recently published a review paper on ”Physics-driven learning for inverse problems in quantum chromodynamics”, from DEEP-IN working group led by Lingxiao Wang (Research Scientist, iTHEMS), including Tetsuo Hatsuda (Program Director, iTHEMS). The authors explore how combining deep learning techniques with physics-driven designs significantly improves the extraction of accurate physical properties from complex QCD phenomena. Highlighting applications such as lattice QCD calculations and studies of hadron interactions, neutron stars, and heavy-ion collisions, the review emphasizes the benefits of embedding physical priors into machine learning models and suggests broader potentials to general physics problems.
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2025-03-06
Paper of the WeekWeek 2, March 2025
Title: Collective Neutrino Oscillations in Three Flavors on Qubit and Qutrit Processors Author: Luca Spagnoli, Noah Goss, Alessandro Roggero, Ermal Rrapaj, Michael J. Cervia, Amol V. Patwardhan, Ravi K. Naik, A. Baha Balantekin, Ed Younis, David I. Santiago, Irfan Siddiqi, Sheakha Aldaihan arXiv: http://arxiv.org/abs/2503.00607v1
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2025-03-06
Hot Topic
RIKEN-Nara Women's University Joint Diversity Promotion Workshop 2025 on March 3, 2025
On March 3 and 4, a total of 19 students from various courses at Nara Women's University—including mathematics, physics, chemistry, biological sciences, and environmental sciences (comprising first-year, second-year, and third-year undergraduate students, as well as first-year master's students)—visited RIKEN. During their visit, they toured several research facilities, including the RIBF Facility at the RIKEN Nishina Center (RNC), the RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS), the Laboratory for Sensorimotor Integration at the RIKEN Center for Brain Science (CBS), the Photonics Control Technology Team at the RIKEN Center for Advanced Photonics (RAP), and the Molecular Bioregulation Research Team at the RIKEN Center for Sustainable Resource Science (CSRS). At each laboratory, the students had the opportunity to engage with cutting-edge research up close, observe experimental equipment, and ask researchers about their work. In the evening, they participated in a networking session with RIKEN researchers, where they explored research topics in depth through iTHEMS members' poster presentations. This interactive session also provided insights into the daily lives and career paths of researchers, offering students valuable inspiration from the research environment. This diversity promotion initiative is a collaborative project between the Faculty of Science at Nara Women's University and the RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS), conducted under the auspices of the RIKEN Diversity Promotion Office. It is organized alongside a series of lectures at Nara Women's University and is planned to continue in the coming years.
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2025-02-27
Paper of the WeekWeek 5, February 2025
Title: Detection of molecular clouds in the PeVatron candidate source LHAASO J0341$+$5258 by the Nobeyama 45-m radio telescope Author: Naomi Tsuji, Shunya Takekawa, Kaya Mori, Alison Mitchell, Shuo Zhang, Priyadarshini Bangale, Stephen DiKerby, Tülün Ergin, Jooyun Woo, Samar Safi-Harb, Shinta Kausya arXiv: http://arxiv.org/abs/2502.15432v1
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2025-02-25
Hot Topic
Farewell message from Jeffrey Fawcett
Our colleague, Jeffrey Fawcett will move on to a new career as a Chief Scientist at Regional Fish Institute, Ltd. as of March 1st, 2025. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Jeffrey Fawcett: I will be moving to Kyoto to work at a company called Regional Fish from March. I will also most likely have a joint position at Kyoto University at a lab funded by the company. The company was started a few years ago mostly be people from Kyoto University, Graduate School of Agriculture, where I did my study, and specializes in breeding and developing fish and aquatic species using genome editing and various other techniques. My task will mainly be to perform genomic data analysis for the company, although I will also have some freedom to pursue my own research. I am looking forward to the new challenge to utilize my expertise and work for a company whose I mission I can identify with. I have been in iTHEMS for exactly 7 years, which say how much I enjoyed and appreciated the setup of iTHEMS. I remember some people telling me its their first time meeting a biologist, whereas I never imagined I would ever have the opportunity to enjoy talks on pure mathematics and theoretical physics. I would like to thank all the people involved in iTHEMS and hopefully I will be able to visit iTHEMS from time to time and keep up the connection.
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2025-02-25
Seminar Report
Visit by ASCENT-6E high school students on January 13, 2025
On Monday, January 13th, 2025, we were glad to receive the visit of 15 high school students (13 female and 2 male) enrolled in the STELLA Program ASCENT-6E of Chiba University. The students, accompanied by the Program Director Prof. Jun Nomura, Prof. Atsushi Tsuji, and Program Coordinators Prof. Qian Wang and Prof. Hina Morishige, were welcome to a one-day workshop organized by iTHEMS members. The workshop consisted of a series of presentations in which iTHEMS members talked about some of the fundamental, yet unresolved, questions about our universe. We covered topics ranging from mathematics, biology, physics, and philosophy of science. The objective was to promote the curiosity of students towards science, using iTHEMS as an example of how scientists from different disciplines may interact and do research together under the same roof. We also took the chance to advertise the different RIKEN programs for young researchers and encouraged the students to follow their dreams of becoming professional scientists. During lunchtime and the interactive sessions, we also enjoyed nice opportunities to converse directly with the students, listen to their particular interests, and answer their questions. This visit by the STELLA program ASCENT-6E students was an invaluable opportunity for us at iTHEMS to understand the current situation of young students, their motivations, and their innovative ideas. For the sake of promoting love for science, inclusivity in academia, and a closer interaction with society, we hope that we can create more bridges between the iTHEMS members and the young students in the future. We are glad that the workshop was a success. Please see the webpage of STELLA Program ASCENT-6E to read some of the comments that students made regarding their visit to iTHEMS. Reported by José Said Gutiérrez-Ortega
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2025-02-25
Seminar Report
Theories of Astrophysical Big Bangs 2025 on February 17, 2025
The international workshop “Theories of Astrophysical Big Bangs 2025” was held at RIKEN from February 17 to 19. During the workshop, Daniel Kasen (UC Berkeley), who is currently on sabbatical at RIKEN, delivered a special lecture on supernovae and kilonovae. In addition, 25 invited talks were presented, allowing participants to share the latest advancements in the field of Astrophysical Big Bangs. The workshop also featured 33 poster presentations, showcasing the diverse range of research in the field and fostering extensive discussions among participants. A total of 83 participants from six countries, including Japan, registered for the workshop. This event was supported by the JST ASPIRE project for top scientists: “RIKEN-Berkeley Mathematical Quantum Science Initiative”, which particularly contributed to strengthening research collaboration between RIKEN and UC Berkeley. The workshop is expected to serve as a catalyst for future joint research endeavors. Reported by Shigehiro Nagataki
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2025-02-20
Paper of the WeekWeek 4, February 2025
Title: Systematic study of the composition of Type I X-ray burst ashes: Neutron star structure v.s. Reaction rate uncertainties Author: Guoqing Zhen, Helei Liu, Akira Dohi, Guoliang Lü, Nobuya Nishimura, Chunhua Zhu, Renxin Xu arXiv: http://arxiv.org/abs/2502.10992v1 Title: Chiral symmetry restoration in QC_2D from effective model using the functional renormalization group Author: G. Fejos, D. Suenaga arXiv: http://arxiv.org/abs/2502.10134v1 Title: Birational Transformations and 2d (0,2) Quiver Gauge Theories beyond Toric Fano 3-folds Author: Dongwook Ghim, Minsung Kho, Rak-Kyeong Seong arXiv: http://arxiv.org/abs/2502.08741v1 Title: Numerical evidence for a CP broken deconfined phase at $θ=π$ in 4D SU(2) Yang-Mills theory through simulations at imaginary $θ$ Author: Mitsuaki Hirasawa, Masazumi Honda, Akira Matsumoto, Jun Nishimura, Atis Yosprakob arXiv: http://arxiv.org/abs/2502.09115v2
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2025-02-20
Seminar Report
Pebbles in Planet Formation on February 10-13, 2025
From February 10 to 13, the workshop "Pebbles in Planet Formation" featured a diverse range of topics, including dust theory, solar system small body exploration, dust experiments, simulations of planetesimal formation via instabilities, and observations of protoplanetary disks. The program included six keynote talks, 40 contributed talks, and 18 poster presentations. Ample time was allocated for coffee breaks and discussion sessions, fostering in-depth conversations on various topics. In particular, the workshop reaffirmed the importance of collaboration between experimental groups in Germany and experimental and theoretical groups in Japan. As a result, we have established a foundation for ongoing communication and future cooperation. Reported by Misako Tatsuuma
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2025-02-13
Paper of the WeekWeek 3, February 2025
Title: Physics-Conditioned Diffusion Models for Lattice Gauge Theory Author: Qianteng Zhu, Gert Aarts, Wei Wang, Kai Zhou, Lingxiao Wang arXiv: http://arxiv.org/abs/2502.05504v1
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2025-02-10
Hot TopicFarewell message from Nozomi Kakinuma
Our administrative staff member, Nozomi Kakinuma, will be leaving RIKEN on February 14 to return to academic research. We will greatly miss her and wish her all the best in her future endeavors. Here is a message from Nozomi: Since April last year, I have been part of iTHEMS as a staff member in the iTHEMS Promotion Office. However, I have recently decided to pursue a career in research. Through coffee meetings, where researchers passionately discussed their work and explained it in an accessible way, I came to deeply appreciate both the excitement and significance of fundamental research. Inspired by these experiences, I am now committed to dedicating myself to research. I am truly grateful for all the support and guidance I have received. Thank you very much.
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2025-02-10
Press Release
Who Is at Higher Risk of Progression from Acute Liver Injury to Acute Liver Failure?
A collaborative research group, including Professor Shingo Iwami (Visiting Scientist, iTHEMS / Professor, Graduate School of Science, Nagoya University), has applied artificial intelligence (AI) technology to clinical research. Through joint research, they discovered that patients with acute liver injury can be classified into three groups based on their treatment response. Furthermore, they successfully developed the world's first AI model capable of predicting which group a patient belongs to using clinical data such as initial blood test results. For more details, please visit Kyushu University’s website via the related links.
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2025-02-06
Paper of the WeekWeek 2, February 2025
Title: Investigating the Bouncing Barrier with Collision Simulations of Compressed Dust Aggregates Author: Haruto Oshiro, Misako Tatsuuma, Satoshi Okuzumi, Hidekazu Tanaka arXiv: http://arxiv.org/abs/2502.03107v1 Title: Renormalization-group approach to the Kohn-Luttinger superconductivity: Amplification of the pairing gap from $\ell^4$ to $\ell$ Author: Yuki Fujimoto arXiv: http://arxiv.org/abs/2502.01169v1 Title: $NJ/ψ$ and $Nη_c$ interactions from lattice QCD Author: Yan Lyu, Takumi Doi, Tetsuo Hatsuda, Takuya Sugiura arXiv: http://arxiv.org/abs/2502.00054v1 Title: Identification of finite circular metric spaces by magnitude and Riesz energy Author: Hiroki Kodama, Jun O'Hara arXiv: http://arxiv.org/abs/2408.06091v3 Title: Computing theta-dependent mass spectrum of the 2-flavor Schwinger model in the Hamiltonian formalism Author: Akira Matsumoto, Etsuko Itou, Yuya Tanizaki arXiv: http://arxiv.org/abs/2501.18960v2 Title: Novel Lattice Formulation of 2D Chiral Gauge Theory via Bosonization Author: Okuto Morikawa, Soma Onoda, Hiroshi Suzuki arXiv: http://arxiv.org/abs/2501.18949v1 Title: Biological invasion by the cycad-specific scale pest Aulacaspis yasumatsui (Diaspididae) into Cycas revoluta (Cycadaceae) populations on Amami-Oshima and Okinawa-jima, Japan Author: Benjamin E. Deloso, José Said Gutiérrez-Ortega, Jui-Tse Chang, Yasuko Ito-Inaba, Anders J. Lindström, L. Irene Terry, John Donaldson, William Tang, Ronald D. Cave, Jorge Antonio Gómez-Díaz, Vanessa M. Handley, M. Patrick Griffith, Thomas E. Marler Journal Reference: Plant Species Biology doi: https://doi.org/10.1111/1442-1984.12505 Title: Spacetime profile of electromagnetic fields in intermediate-energy heavy-ion collisions Author: Hidetoshi Taya arXiv: http://arxiv.org/abs/2501.18171v1
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2025-01-31
Seminar Report
Quantum Computation SG Seminar by Suguru Endo on January 28, 2025
In this 2-day lecture, Dr. Endo reviewed quantum error mitigation, which offers a practical approach to reducing errors in noisy intermediate-scale quantum (NISQ) devices without requiring the encoding of qubits. The first day started by discussing the fundamentals of noise modeling in quantum systems, and then we overviewed concrete examples of QEM techniques, including extrapolation, probabilistic error cancellation (PEC), virtual distillation, quantum subspace expansion, and Clifford data regression. After that, the lecturer presented advanced QEM methods, such as the stochastic PEC approach, which mitigates the effects of Lindblad terms in Lindblad master equations and the generalized quantum subspace expansion, which is a unified framework of QEM. In the second day, the lecturer introduced recent research topics including information-theoretic analysis of QEM, connections to non-Markovian dynamics, combination of QEM with quantum error correction toward the early fault-tolerant quantum computing era. The lecture attracted attendees with wide research backgrounds ranging from quantum information to condensed matter, nuclear, and particle physics. Reported by Yuta Sekino
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2025-01-30
Paper of the WeekWeek 5, January 2025
Title: $Λ$(1405) in the flavor SU(3) limit using a separable potential in the HAL QCD method Author: Kotaro Murakami, Sinya Aoki arXiv: http://arxiv.org/abs/2501.17423v1 Title: Multi-Messenger and Cosmological Constraints on Dark Matter through Two-Fluid Neutron Star Modeling Author: Ankit Kumar, Sudhakantha Girmohanta, Hajime Sotani arXiv: http://arxiv.org/abs/2501.16829v1 Title: Left-hand cut and the HAL QCD method Author: Sinya Aoki, Takumi Doi, Yan Lyu arXiv: http://arxiv.org/abs/2501.16804v1 Title: Reconstruction of QCD first-order phase transition from neutron star measurements Author: Ronghao Li, Sophia Han, Zidu Lin, Lingxiao Wang, Kai Zhou, Shuzhe Shi arXiv: http://arxiv.org/abs/2501.15810v1 Title: Synthesis of a semimetallic Weyl ferromagnet with point Fermi surface Author: Ilya Belopolski, Ryota Watanabe, Yuki Sato, Ryutaro Yoshimi, Minoru Kawamura, Soma Nagahama, Yilin Zhao, Sen Shao, Yuanjun Jin, Yoshihiro Kato, Yoshihiro Okamura, Xiao-Xiao Zhang, Yukako Fujishiro, Youtarou Takahashi, Max Hirschberger, Atsushi Tsukazaki, Kei S. Takahashi, Ching-Kai Chiu, Guoqing Chang, Masashi Kawasaki, Naoto Nagaosa, Yoshinori Tokura Journal Reference: Nature (2025) doi: https://doi.org/10.1038/s41586-024-08330-y Title: Grassmann Tensor Renormalization Group for two-flavor massive Schwinger model with a theta term Author: Hayato Kanno, Shinichiro Akiyama, Kotaro Murakami, Shinji Takeda arXiv: http://arxiv.org/abs/2501.14086v1 Title: Pair Correlation of Zeros of the Riemann Zeta Function I: Proportions of Simple Zeros and Critical Zeros Author: Siegfred Alan C. Baluyot, Daniel Alan Goldston, Ade Irma Suriajaya, Caroline L. Turnage-Butterbaugh arXiv: http://arxiv.org/abs/2501.14545v1
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2025-01-29
Press Release
Make it worth Weyl: engineering the first semimetallic Weyl quantum crystal
An international research team, including Ching-Kai Chiu (Senior Research Scientist, iTHEMS) and led by the Strong Correlation Quantum Transport Laboratory of the RIKEN Center for Emergent Matter Science (CEMS) has achieved a world-first by realizing an ideal Weyl semimetal, marking a major breakthrough in quantum materials research. Weyl fermions emerge as quantum excitations of electrons in crystals and are predicted to exhibit exotic electromagnetic properties. However, previous Weyl materials were often overshadowed by unwanted electronic states, making it difficult to observe pure Weyl fermion behavior. The team successfully engineered an ideal Weyl semimetal by precisely controlling the composition of the topological semiconductor (Cr,Bi)2Te3, eliminating irrelevant electronic states. Published in Nature, this work opens new possibilities for terahertz (THz) light devices and next-generation electronics. For more details, please refer to the related link.
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2025-01-28
Award
Lingxiao Wang received the “Best ‘Physics for AI’ Paper Award”
Our colleague Lingxiao Wang (Research Scientist, iTHEMS) has received the “Best ‘Physics for AI’ Paper Award” of the Machine Learning and the Physical Sciences Workshop. The winning paper is entitled “Higher-order cumulants in diffusion models”. Congratulations, Lingxiao!
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2025-01-24
Hot Topic
Farewell message from Liang Zhang
Our colleague, Liang Zhang, has returned to the Shanghai Institute of Applied Physics at the University of Chinese Academy of Sciences to complete his PhD thesis. We will all miss him and wish him the very best of luck in successfully defending his thesis ! Here is a message from Liang Zhang: I joined iTHEMS in January 2023 as a joint student and completed my two-year journey here in January 2025. I initially joined iTHEMS to study lattice QCD and the HAL QCD method, and I am deeply grateful to Hatsuda-san and Doi-san for guiding me into this fascinating field. However, I soon realized that my experience at iTHEMS extended far beyond my original purpose. For example I had a discussion with Namba san on chiral symmetry breaking which is studied in both particle physics and cosmology. It left an immediate impression that physics is so universal other than reading such sentences in textbooks. And the interdisciplinary energy at iTHEMS constantly amazed me. When I first came here I always struggled to pinpoint people’s major. In some seminars, theoretical physicists gave a biology talk (like Christy)! I vaguely feel like there is a group theory for nature which can be expressed to different representations, biological, mathematical, physical, etc. Is this what the “i” in iTHEMS means? At last I would like to thank everyone in iTHEMS again for my two-year experience here. This experience gives me a great impulse to expand the possibilities of my future research life. iTHEMS’s uniqueness lies in its boundless possibilities. And I dearly hope our paths will cross again!
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2025-01-23
Paper of the WeekWeek 4, January 2025
Title: Numerical simulation of fractional topological charge in $SU(N)$ gauge theory coupled with $\mathbb{Z}_N$ 2-form gauge fields Author: Motokazu Abe, Okuto Morikawa arXiv: http://arxiv.org/abs/2501.11438v1 Title: On the connected sums of the $(2,1)$-cable of the figure eight knot Author: Yoshihiro Fukumoto, Masaki Taniguchi arXiv: http://arxiv.org/abs/2501.07910v1 Title: Lifetime measurement of the muonic atom of enriched Si isotopes Author: R. Mizuno, M. Niikura, S. Akamatsu, T. Fujiie, K. Ishida, T. Ito, T. Kikuchi, T. Matsuzaki, F. Minato, J. Murata, T. Naito, K. Shimomura, S. Takeshita, I. Umegaki, Y. Yamaguchi arXiv: http://arxiv.org/abs/2501.05897v1 Title: On the slice-torus invariant $q_M$ from $\mathbb{Z}_2$-equivariant Seiberg--Witten Floer cohomology Author: Nobuo Iida, Taketo Sano, Kouki Sato, Masaki Taniguchi arXiv: http://arxiv.org/abs/2501.07788v1 Title: Tridiagonal Hamiltonians modeling the density of states of the Double-Scaled SYK model Author: Pratik Nandy Journal Reference: JHEP 01 (2025) 072 doi: https://doi.org/10.1007/JHEP01(2025)072 arXiv: http://arxiv.org/abs/2410.07847v2
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2025-01-17
Hot Topic
Farewell message from Lucy McNeill
Our colleague Lucy McNeill has moved on to a new career as a Hakubi Assistant Professor at The Hakubi Center for Advanced Research, Kyoto University as of January 16, 2025. We all will miss her and wish her the best of luck in her latest endeavor. Here is a message from Lucy McNeill: During my 1 year at iTHEMS as a postdoctoral researcher, I was presented with opportunities to further both my own research and professional development at every turn. I am especially grateful for iTHEMS directors and colleagues' support in starting the "asymptotics in astrophysics" iTHEMS study group, ample chances to travel abroad to share my work, and the frequent international workshops organised at iTHEMS. In particular, workshops co-hosted with RIKEN-Berkeley left this lasting impression on me; that new stellar astrophysics and supernova physics paradigms are creatively and efficiently conceived when physicists, mathematicians and data scientists join forces to solve longstanding astrophysical puzzles. iTHEMS is such a special place where those necessary first interactions are regularly facilitated, and I am sad to leave. But... "I'll be back"!
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2025-01-16
Paper of the WeekWeek 3, January 2025
Title: Direct Monte Carlo computation of the 't~Hooft partition function Author: Okuto Morikawa, Hiroshi Suzuki arXiv: http://arxiv.org/abs/2501.07042v1 Title: Impact of dark matter distribution on neutron star properties Author: Ankit Kumar, Hajime Sotani arXiv: http://arxiv.org/abs/2501.07052v1 Title: Physics-Driven Learning for Inverse Problems in Quantum Chromodynamics Author: Gert Aarts, Kenji Fukushima, Tetsuo Hatsuda, Andreas Ipp, Shuzhe Shi, Lingxiao Wang, Kai Zhou Journal Reference: Nature Reviews Physics (2025) doi: https://doi.org/10.1038/s42254-024-00798-x arXiv: http://arxiv.org/abs/2501.05580v1
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2025-01-10
Hot Topic
Farewell message from Yantao Wu
Our colleague Yantao Wu will move on to a new career as a faculty member at Institute of Physics, Chinese Academy of Sciences as of January 10, 2025. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Yantao Wu: I joined iTHEMS in June 2021 as a RIKEN-Berkeley fellow, and have stayed here for three years and a half now. iTHEMS is a precious rare place in the academic world, where there seems to be no responsibility, no one telling you what to do, and infinite space for travel; where there seems to be a curious mind on every subject and every question ought to be asked. The interdisciplinary nature of the group has forever left an imprint on me, and I will always remember the vivid biological facts and mathematical tricks that I have learned here. Entering as a condensed matter physicist and leaving as a condensed matter physicist, my heart will always have a spot for the particle theory which I have learned from here. It has been an unexpected, yet very pleasant mix. Sadly, it appears that every gathering ends somewhere, and I need to leave this warm and protective bubble to a new place, to really enter the grown world of independent research and start my own group. iTHEMS will always remain as a source of lasting encouragement. I will move to the Institute of Physics, Chinese Academy of Sciences in Beijing to start a faculty position. If you ever want to visit, please let me know you are from iTHEMS and I will make you a cup of tea (amidst taking you to the great wall and covering your travel costs.)
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2025-01-10
Press Release
Discovery of Measurement-Induced Spectral Phase Transition in Quantum Systems
A collaborative research team, including Ryusuke Hamazaki (Senior Research Scientist, iTHEMS / RIKEN Hakubi Team Leader, Nonequilibrium Quantum Statistical Mechanics RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research (CPR)), has discovered a spectral phase transition in quantum systems under measurement. This research is expected to bridge the gap between two seemingly distinct phenomena: the recently emerging field of “measurement-induced phase transitions in nonequilibrium quantum systems" and the long-studied "phase transitions in equilibrium quantum systems." By discovering the analogy between these transitions, this work paves the way for a deeper understanding of quantum many-body systems. Using a method known as Lyapunov analysis, the team demonstrated the existence of spectral phase transitions in quantum systems under measurement. Furthermore, they found that the critical point of these spectral phase transitions coincides with the critical point of entanglement transitions. For more details, please refer to the related link.
53 news in 2025