News
173 news in 2025
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2025-08-27
Person of the Week
Self-introduction: Wei-Hsiang Shao
My name is Wei-Hsiang Shao (ウェイシャン シャオ). I completed my PhD in Physics in the String Theory Group at National Taiwan University in June 2025, and this postdoctoral position marks my first long-term research experience at an academic institute abroad. My research interests lie in quantum gravity, with a particular focus on the nonperturbative aspects of string theory and their implications for our understanding of the universe. Much of our current framework relies on perturbative quantum gravity, which combines Einstein’s General Relativity with local quantum field theory into a low-energy effective theory valid on large scales compared to the Planck scale. While remarkably successful, this framework leaves many open questions—such as Hawking’s black hole information paradox, the origin of our universe, and the recent tensions in cosmological observations. During my PhD, I worked with my supervisors to explore a new perspective on the quantum aspects of black holes by incorporating properties rooted in string theory. Our findings suggest that nonperturbative features of string theory may lead to qualitatively different outcomes for black hole evaporation than those predicted by standard low-energy effective theories. This line of study has inspired me to extend our top-down approach to other contexts, such as the early universe, in the hope of uncovering nonperturbative quantum gravity effects that could reshape the current cosmological model. I am very excited to exchange ideas with colleagues here, to broaden my perspective by learning from experts across different areas, and to contribute to this vibrant research environment through my endeavors.
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2025-08-26
Hot Topic
Workshop: N3AS Annual Meeting 2025 (August 5–7 @ UC Berkeley)
We (Keiya Hirashima, Camilia Demidem, Gabriele Di Ubaldo, Jan Schuette-Engel, Yuuka Kanakubo, Yuki Fujimoto, Shuntaro Aoki, Hiro Nagataki, Satoshi Iso, and Tetsuo Hatsuda) attended the N3AS Annual Meeting 2025, held at UC Berkeley (UCB) on August 5–7. N3AS stands for the Network for Neutrinos, Nuclear Astrophysics, and Symmetries, an NSF-funded program that began in 2016. iTHEMS and ABBL joined N3AS in 2020. During the meeting, Keiya, Camilia, Jan, Yuki and Shuntaro gave excellent presentations on their recent research. We also enjoyed many fascinating talks from N3AS members, including Mia Kumamoto and Kelsey Lund, both of whom participated in iTHEMS Now and Next 2025. Tetsuo and Hiro reported on the activities of iTHEMS, RBC, and ABBL, while Wick Haxton (PI of the N3AS program) provided an update on the status of N3AS. The meeting took place in the Physics building, where the RIKEN-Berkeley Center (RBC) is located. RBC is a hub for international collaboration of iTHEMS, such as researcher exchanges, joint workshops, and long-term fellowships. Now 3 researchers of iTHEMS (Jan, Gabriele, Yuuka) are staying there and engaging in international research collaborations. We made good use of the RBC office during our stay in the week of August 3. While at Berkeley, we (Satoshi, Tetsuo, and Hiro) had the opportunity to meet with Steve Kahn (Dean of Mathematical & Physical Sciences, UC Berkeley) and Martin Olsson (Chair of the Department of Mathematics, UC Berkeley) to discuss future communication and collaboration between iTHEMS and the Departments of Physics and Mathematics at UCB. We also visited Lawrence Berkeley National Laboratory (LBNL), where another iTHEMS office is located. This visit reaffirmed the importance of the strong connection between RIKEN and Berkeley, and the key role of the RBC in supporting this collaboration.
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2025-08-26
Hot Topic
Exhibited “Black Hole Recorder” at Expo 2025 Osaka, Kansai: A Quantum Gravity Science-Art Project Recording Messages for the Future
iTHEMS exhibited “Black Hole Recorder,” a science art work based on quantum black hole theory created in collaboration with external creators in 2021, at the 2025 Japan International Exposition (Osaka-Kansai Expo) special exhibition "Entangled Moment - [Quantum, Sea, Universe] × Art" (hosted by the Cabinet Office and the Ministry of Education, Culture, Sports, Science and Technology) from August 14 (Thu) to August 20 (Wed), 2025. The exhibition featured research from nearly 20 research institutions and companies, along with approximately 20 artworks, presented across nine sections. The venue was designed to evoke a world where the microscopic quantum realm and the vast universe continuously cycle and regenerate like an “Ouroboros.” iTHEMS was the ninth and final section in the exhibition, where visitors could view the artwork alongside its explanation. Additionally, all sounds in the venue were continuously recorded using the “Black Hole Recorder,” and visitors were invited to record messages for 1,500 years in the future, with plans to eventually transmit the recorded sounds to a black hole via radio waves. Given the Expo setting, on many days the venue welcomed over 9,000 visitors daily (62,360 visitors over 7 days), allowing many people to experience and enjoy the exhibition. However, during peak hours, the venue became quite crowded, making it difficult for some visitors to view the exhibits at their leisure. Through the artworks, we were able to introduce visitors to black holes and the underlying theory of quantum gravity, and I believe many left with the message that these foundational theories may one day lead to useful technologies. Participating in this exhibition at the Expo provided a valuable opportunity to convey research findings and messages to those who typically have little interest in science. The exchange with other exhibitors also contributed to the future development of iTHEMS's social collaboration activities.
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2025-08-21
Paper of the WeekWeek 4, August 2025
Title: Quasiprobability Thermodynamic Uncertainty Relation Author: Kohei Yoshimura, Ryusuke Hamazaki arXiv: http://arxiv.org/abs/2508.14354v1 Title: Antiferromagnetic Long-Range Order in a Lattice Fermion Model Author: Yukimi Goto, Tohru Koma arXiv: http://arxiv.org/abs/2508.12421v1 Title: The NN$Ω_{ccc}$ Bound-States with the HAL QCD interaction Author: Faisal Etminan arXiv: http://arxiv.org/abs/2508.12276v1 Title: Scaling Behaviors in Active Model B+ via the Functional Renormalization Group Author: Gergely Fejős, Zsolt Szép, Naoki Yamamoto arXiv: http://arxiv.org/abs/2508.12065v1 Title: Sample efficient likelihood-free inference for virus dynamics with different types of experiments Author: Yingying Xu, Ulpu Remes, Enrico Rinaldi, Henri Pesonen arXiv: http://arxiv.org/abs/2508.11042v1 Title: The Alternative Hypothesis for Zeros of the Riemann Zeta-Function Author: Siegfred Alan C. Baluyot, Daniel Alan Goldston, Ade Irma Suriajaya, Caroline L. Turnage-Butterbaugh arXiv: http://arxiv.org/abs/2508.10857v1 Title: Probing Nucleon-$Ω_{\rm ccc}$Interaction via Lattice QCD at Physical Quark Masses Author: Liang Zhang, Takumi Doi, Yan Lyu, Tetsuo Hatsuda, Yu-Gang Ma arXiv: http://arxiv.org/abs/2508.10388v1
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2025-08-20
Hot Topic
Farewell message from Congcong Le
Our colleague, Congcong Le, will be leaving iTHEMS to join the Hefei National Laboratory as a Research Scientist. Since joining iTHEMS in August 2021 as a Postdoctoral Researcher, he has spent four wonderful years making progress in research and actively engaging in our community. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Congcong: I joined iTHEMS in August 2021 as a Postdoctoral Researcher and have spent four wonderful years here. Looking back on this journey, I have not only made significant progress in my research but have also felt immense warmth and care in my daily life. For researchers, the most valuable thing is to have an open environment where we can freely explore ideas, follow our curiosity, and ask every question that comes to mind. iTHEMS has provided such an environment, and I consider myself very lucky to have been part of it. In our weekly Coffee Meetings, I always benefit from the vivid biological facts and mathematical tricks. In the weekly group discussions hosted by Chingkai, I can share the new problems and the new ideas, and these exchanges have continually broadened my perspective and strengthened my research abilities. On a personal note, I am especially grateful to Hatsuda-san and all the iTHEMS assistants. During a challenging time for my family, they offered us sincere support and help. I still clearly remember that when we arrived in Japan from Germany in 2021, my wife was pregnant. Due to COVID-19, we needed to quarantine. To ensure my wife’s safety, Tomoko-san and Sasaki-san helped us find a hotel near the hospital, and after the quarantine, Hatsuda-san personally drove my family and me to RIKEN. This kindness and care will always remain in my heart. Next, I will be moving to the Hefei National Laboratory in China. Although I am embarking on a new journey, I sincerely hope to return often to visit and continue enjoying the unique academic atmosphere here. Let’s stay in touch and keep enjoying the beauty of both research and life.
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2025-08-18
Hot TopicExhibition of the Science-Art Work “Black Hole Recorder” at Expo 2025 Osaka, Kansai, Japan
The science-art work Black Hole Recorder, created in 2021 by iTHEMS in collaboration with external creators and based on quantum black hole theory, will be exhibited at the special exhibition “Entangled Moments — [Quantum, Ocean, Universe] × Art” (hosted by the Cabinet Office and the Ministry of Education, Culture, Sports, Science and Technology) at Expo 2025 Osaka, Kansai, Japan, from Thursday, August 14 to Wednesday, August 20, 2025. To mark the exhibition, a YouTube video introducing Black Hole Recorder has been released, along with a digest version of a dialogue between physicists: Atsuto Iso (Director, iTHEMS, RIKEN) × Nomura (Director, Berkeley Center for Theoretical Physics), discussing quantum gravity and black holes. For details, please refer to the related links.
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2025-08-18
Hot Topic
Farewell message from Misako Tatsuuma
Our colleague, Misako Tatsuuma, will be joining the Department of Electronic Engineering, National Institute of Technology, Tokyo College as an Assistant Professor starting September 2025. She will continue to be involved with iTHEMS as a visiting scientist. We will all miss her and wish her the best of luck in this new endeavor. Here is a message from Misako: Although it has only been about two years since October 2023, my time at iTHEMS has been a lifelong treasure for me. My research field is planet formation theory, but by joining seminars from many different fields, I was able to learn a lot of new things and gain many new ideas for future research. I also had opportunities to engage in outreach and teaching, which gave me valuable experiences. I am especially grateful that, during the most difficult period of childcare, I was allowed to work flexibly, including working from home. I will continue to be involved with iTHEMS as a visiting scientist, so I look forward to staying connected with you. From September 2025, I will be teaching in the field of information engineering at a National Institute of Technology (KOSEN), which is a five-year school for students from the equivalent of the first year of high school to the second year of university. This will be a new field for me, so I hope to learn a lot while also incorporating what I can into my research. Thank you very much for everything.
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2025-08-18
Seminar ReportiTHEMS Theoretical Physics Seminar by Sergei Ketov on July 8, 2025
After a review of Starobinsky inflation, it is demonstrated how it fits both Planck and ACT observations, even in the presence of production of primordial black holes (as dark matter) at smaller scales. The Swampland Program constraints on the Starobinsky inflation are resolved also. Further constraints to inflation in the supergravity framework, arising via renormalization of precision LHC physics on electroweak scales are briefly outlined. Reported by Shuntaro Aoki
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2025-08-14
Paper of the WeekWeek 3, August 2025
Title: On continuum and resonant spectra from exact WKB analysis Author: Okuto Morikawa, Shoya Ogawa arXiv: http://arxiv.org/abs/2508.09211v1 Title: Time Ordering Effects and Destruction of Quasiparticles in Two-dimensional Holographic CFTs Author: Weibo Mao, Masahiro Nozaki arXiv: http://arxiv.org/abs/2508.07645v1
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2025-08-07
Paper of the WeekWeek 2, August 2025
Title: New computational methods in lattice gauge theory -- quantum computation and tensor networks Author: Etsuko Itou arXiv: http://arxiv.org/abs/2508.03126v1 Title: Lattice results for the equation of state in dense QCD-like theories Author: Etsuko Itou arXiv: http://arxiv.org/abs/2508.03090v1 Title: Bound states of $ _{c\bar{c}}^{9}$Be within $c\bar{c}+α+α$ cluster models based on state-of-the-art HAL QCD charmonium-nucleon interactions Author: Faisal Etminan arXiv: http://arxiv.org/abs/2508.02653v1 Title: Parametric pair production of collective excitations in a Bose-Einstein condensate Author: Victor Gondret, Rui Dias, Clothilde Lamirault, Léa Camier, Amaury Micheli, Charlie Leprince, Quentin Marolleau, Scott Robertson, Denis Boiron, Christoph I. Westbrook arXiv: http://arxiv.org/abs/2508.01654v1 Title: Universal Time Evolution of Holographic and Quantum Complexity Author: Masamichi Miyaji, Shan-Ming Ruan, Shono Shibuya, Kazuyoshi Yano arXiv: http://arxiv.org/abs/2507.23667v1
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2025-08-07
Press Release
Discovery of Universal Laws of Quantum Entanglement Across Dimensions
Unraveling the structure of quantum entanglement is a central challenge in both theoretical physics and quantum information science. However, much of the research to date has been limited to 1+1 dimensions. Analyzing entanglement structures becomes significantly more difficult beyond 1+1 dimensions, and new methods for investigating higher-dimensional entanglement structures have been long sought. A collaborative research group including Yuya Kusuki (Visiting Scientist, iTHEMS) focused on a technique known as the "thermal effective theory," which has recently made significant advances in analyzing higher-dimensional theories in particle physics. By introducing this approach to quantum information, they successfully uncovered universal behaviors underlying the structure of quantum entanglement in quantum systems of arbitrary dimensions. For more details, please refer to the related links.
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2025-08-06
Hot Topic
RIKEN Wako Science Camp 2025 — High School Students Challenged the Violation of Bell’s Inequality with a Quantum Computer
Sixteen high school students selected from across Japan gathered at RIKEN Wako Campus to participate in the "RIKEN Wako Science Camp 2025." Divided into three courses based on their applications, the students joined one of the following research units: Inter-Individual Brain Dynamics Collaboration Unit (CBS), Molecular Ligand Target Research Team (CSRS), and RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS). Over the four-day program held from July 28 to 31, 2025, they experienced cutting-edge science and technology in an immersive camp-style setting. At iTHEMS, Masazumi Honda and Ryo Namba led Course C: "Exploring the Quantum World – Observing the Violation of Bell’s Inequality on a Quantum Computer." In this course, students used an actual cloud-based quantum computer provided by IBM Quantum to investigate and experimentally verify the violation of Bell’s inequality, which demonstrates the fundamental departure of quantum theory from classical physics. The students showed remarkable enthusiasm and drive. Despite the fact that the topic went far beyond the scope of high school-level mathematics and physics, they not only implemented the necessary programs on the quantum computer to verify the violation of Bell’s inequality, but also developed their own original methods, impressing the researchers in charge. In addition to the hands-on activities, the students toured RIKEN’s in-house quantum computer "A" and supercomputer "HOKUSAI," experienced "A" through VR, and visited exhibitions at the Nishina Center. While deepening friendships with like-minded peers, they also interacted informally with other researchers at iTHEMS over lunch and coffee breaks, gaining firsthand insight into the life of a real scientist — sparking reflections on their own future paths. The four-day program concluded by the students' presentations on what they had learned and experienced during the camp in front of fellow students and instructors, as well as RIKEN's president and executive directors, on the final day. RIKEN Wako Science Camp is an annual program by RIKEN for high school students, traditionally focused on experimental sciences. This year marked the first time a theoretical course was offered, with iTHEMS researchers taking on the role of instructors.
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2025-08-04
Featured Paper of the Week
Threats to cycad biocultural heritage in the Amami Islands, Japan
We are pleased to introduce this paper, which has been selected as an Editor’s Choice. Species are products of evolution, and once they are lost due to extinction, they can’t be recovered. Unfortunately, the actions of humans have threatened species worldwide in various ways, and one indirect method has been the unintentional introduction of invasive species. A species is “invasive” when it enters a habitat that is not where it evolved. In the absence of natural predators, ecological pressures, or competitors, invasive species may proliferate without control, directly harming native species or indirectly consuming resources necessary for their survival. A case of biological invasion in Japan occurred recently in 2021, when the cycad aulacaspis scale (CAS) insect was detected on the Amami-Oshima and Okinawa-jima, in the Ryukyus. As its name suggests, CAS feeds on cycad plants —and is voracious—, consuming cycads until causing their death. Many places in the islands, historically abundantly populated by the native cycad Cycas revoluta, are now being devastated by this invasion. Many cycad populations are threatened and at risk of extirpation if the invasion is not controlled. But what does it mean when a species is threatened? Of course, losing a species due to the action of humans is a disgraceful event; a part of evolution is lost, and species removal may cause the extinction of other ecologically associated species (pollinators, for example). However, it is also important to consider cases where the threatened species is a significant symbol and a cornerstone of a culture's identity. This is the case of the cycads in the Ryukyus. Cycads have a strong historical significance for the culture of this region: people use them as a source of food, as materials to craft tools, and as a symbol of their local identity. The cycad culture in Japan is already in decline due to an aging demography, migration from rural to urban areas, and modernity in general. With the CAS invasion, the cycads and the culture around them are more threatened than ever, and conservation actions are necessary. In this article, we discuss that biological conservation is not only concerned with our responsibility to take care of nature, but also to take care of cultural identities. Cultures are entangled with their local biodiversity, and joining efforts from scientists in the natural and humanities sciences can help us see the whole picture. Interdisciplinarity is crucial in conservation.
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2025-07-31
Paper of the WeekWeek 5, July 2025
Title: Neural network extraction of chromo-electric and chromo-magnetic gluon masses Author: Jie Mei, Lingxiao Wang, Mei Huang arXiv: http://arxiv.org/abs/2507.22012v1 Title: Tidal heating in detached double white dwarf binaries Author: Lucy O. McNeill, Ryosuke Hirai arXiv: http://arxiv.org/abs/2507.21821v1 Title: Dynamical symmetry breaking in Georgi-Glashow chiral-gauge theories Author: Hao-Lin Li, Álvaro Pastor-Gutiérrez, Shahram Vatani, Ling-Xiao Xu arXiv: http://arxiv.org/abs/2507.21208v1 Title: Celestial Holography meets dS/CFT Author: Hideo Furugori, Naoki Ogawa, Sotaro Sugishita, Takahiro Waki arXiv: http://arxiv.org/abs/2507.17558v1 Title: Probing $ φ$N interaction through bound states of $_φ^{6}\textrm{He} $ mesic nuclei within $ φ\textrm{N-}α$ cluster model Author: Faisal Etminan arXiv: http://arxiv.org/abs/2507.17022v1 Title: Effective Dynamics of Spherically Symmetric Static Spacetime Author: Etera R. Livine, Yuki Yokokura arXiv: http://arxiv.org/abs/2507.18345v1
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2025-07-28
Press Release
A more complete expansion for black hole ringdown waveforms
Each musical instrument has its own unique sound spectrum. Similarly, a ringing black hole emits gravitational waves with its own characteristic frequencies (or “quasinormal modes.”) Black hole spectroscopy is the program of measuring how black holes “ring down” to infer their properties, just as we recognize a musical instrument by the sound it makes. However, black hole signals are more complex than free oscillations. For example, the long-range nature of gravity produces slowly decaying “tails” that quasinormal modes cannot capture — i.e., quasinormal modes are an incomplete basis. In addition, the quasinormal mode spectrum is unstable under small environmental modifications. If we think of the black hole as a musical instrument and enclose it in a room, its modes behave like echoes reflecting against the walls. This spectral instability challenges the robustness of black hole spectroscopy. A research team including Naritaka Oshita (Visiting Scientist, iTHEMS) has turned this challenge into an opportunity. They showed that a set of destabilized quasinormal modes is actually a more complete basis to expand gravitational waveforms, as it can capture the tail components missed by ordinary modes. This discovery paves the way for more accurate ringdown models and improvements in gravitational wave data analysis.
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2025-07-25
Hot Topic
Investigating the World Inside the Atom: Interview with Yan Lyu published on the JICFuS Website
An interview with Dr. Yan Lyu (Postdoctoral Researcher, iTHEMS), titled “Investigating the World Inside the Atom” has been published on the JICFuS (Joint Institute for Computational Fundamental Science) website. Dr. Lyu explores lattice QCD (quantum chromodynamics) through large-scale numerical simulations using supercomputers. In the article, he discusses how he became interested in this field, the interplay between theory and computation, collaborative research through JICFuS, and his personal approaches to research. This inspiring interview offers insight into his journey as a researcher striving to understand the hidden structure of matter. Please see the related link below to read the full article.
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2025-07-24
Press Release
How our body keeps time in the heat
Researchers led by Gen Kurosawa at the RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) in Japan have used theoretical physics to discover how our biological clock maintains a consistent 24-hour cycle—even as temperatures change. They found that this stability is achieved through a subtle shift in the “shape” of gene activity rhythms at higher temperatures, a process known as waveform distortion. This process not only helps keep time steady but also influences how well our internal clock synchronizes with the day-night cycle. The study was published in PLOS Computational Biology on July 22. For further details, please refer to the related links below.
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2025-07-24
Paper of the WeekWeek 4, July 2025
Title: Preface of Special Feature “Current topics on cycad biology: Deciphering the Rosetta Stone of plant evolution.” Part I: Conservation of biological and cultural heritage Author: José Said Gutiérrez-Ortega Journal Reference: Plant Species Biology doi: https://doi.org/10.1111/1442-1984.70016 Title: On the existence of a singular limit equation for a model of a self-propelled object motion Author: Masaharu Nagayama, Koya Sakakibara, Keisuke Takasao arXiv: http://arxiv.org/abs/2507.16447v1 Title: Tensor-Product Bitstring Selected Configuration Interaction Author: Enhua Xu, William Dawson, Himadri Pathak, Takahito Nakajima arXiv: http://arxiv.org/abs/2503.10335v3 Title: Deformations of Standard Locally Homogeneous Spaces Author: Kazuki Kannaka, Toshiyuki Kobayashi arXiv: http://arxiv.org/abs/2507.14832v1 Title: Higher Structures on Boundary Conformal Manifolds: Higher Berry Phase and Boundary Conformal Field Theory Author: Yichul Choi, Hyunsoo Ha, Dongyeob Kim, Yuya Kusuki, Shuhei Ohyama, Shinsei Ryu arXiv: http://arxiv.org/abs/2507.12525v1
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2025-07-24
Seminar Report
iTHEMS Theoretical Physics Seminar by Kensuke Kakimoto on July 23, 2025
In this seminar, mesoscopic transport between a one-dimensional chain with two-body loss, which is realizable with ultracold atoms, is discussed. Based on the Keldysh Green’s function formalism in combination with a noise-field representation of Lindblad dynamics, the obtained particle current exhibits a weaker suppression compared with that under one-body loss, in agreement with a recent experimental observation. Reported by Yuta Sekino
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2025-07-17
Paper of the WeekWeek 3, July 2025
Title: Wavefunction-based operator optimization for two-hadron systems in lattice QCD Author: Yan Lyu, Sinya Aoki, Takumi Doi, Tetsuo Hatsuda, Kotaro Murakami, Takuya Sugiura arXiv: http://arxiv.org/abs/2507.09933v1 Title: Decoding Two-Particle States in QCD with Spatial Wavefunctions Author: Yan Lyu, Sinya Aoki, Takumi Doi, Tetsuo Hatsuda, Kotaro Murakami, Takuya Sugiura arXiv: http://arxiv.org/abs/2507.09930v1 Title: Theoretical evaluation of decay mode of $ {}^{229m} \mathrm{Th} $ in solid samples Author: Ryotaro Masuda, Tomoya Naito, Masashi Kaneko, Hiroyuki Kazama, So Hashiba, Kosuke Misawa, Yoshitaka Kasamatsu arXiv: http://arxiv.org/abs/2507.09064v1 Title: Supernova-induced binary-interaction-powered supernovae: a model for SN2022jli Author: Ryosuke Hirai, Philipp Podsiadlowski, Peter Hoeflich, Maxim V. Barkov, Conrad Chan, David Liptai, Shigehiro Nagataki arXiv: http://arxiv.org/abs/2507.09974v1 Title: Hadron-Hadron Interactions from Lattice QCD: Theory meets Experiments Author: Tetsuo Hatsuda arXiv: http://arxiv.org/abs/2507.08359v1
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2025-07-17
Research News
RIKEN NEWS: Interview with the Executive Director of Science — Unlocking the Future through the Synergy of Mathematical, Computational, and Information Sciences
An interview with Tetsuo Hatsuda (Executive Director of Science, RIKEN / Director, the Division of Applied Mathematical Science, RIKEN iTHEMS) has been featured in the Close-up RIKEN 2025 series on RIKEN’s research introduction page. To leverage RIKEN’s strength in integrated research capabilities and to ensure more strategic and effective operations, RIKEN introduced a new structure in FY2025 consisting of five “Research Domains.” Each domain is headed by an Executive Director of Science—a scientist with internationally recognized excellence and profound insight into both academic research and its administration. This system is designed to promote interdisciplinary collaboration rooted in advanced expertise, thereby accelerating the creation of new knowledge. Supporting the Executive Directors of Science in driving research forward are the Promotion Directors. This interview explores the aims of the Mathematical, Computational, and Information Sciences Domain from the perspectives of both researchers and administrative staff. Please see the related links for the full article.
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2025-07-10
Paper of the WeekWeek 2, July 2025
Title: Neural Unfolding of the Chiral Magnetic Effect in Heavy-Ion Collisions Author: Shuang Guo, Lingxiao Wang, Kai Zhou, Guo-Liang Ma arXiv: http://arxiv.org/abs/2507.05808v1 Title: Pair Correlation Conjecture for the zeros of the Riemann zeta-function II: The Alternative Hypothesis Author: Daniel A. Goldston, Junghun Lee, Jordan Schettler, Ade Irma Suriajaya arXiv: http://arxiv.org/abs/2507.06823v1 Title: Quantum Machine Learning for Identifying Transient Events in X-ray Light Curves Author: Taiki Kawamuro, Shinya Yamada, Shigehiro Nagataki, Shunji Matsuura, Yusuke Sakai, Satoshi Yamada Journal Reference: ApJ 987 105 (2025) doi: https://doi.org/10.3847/1538-4357/adda43 arXiv: http://arxiv.org/abs/2507.05589v1 Title: Zariski-dense deformations of standard discontinuous groups for pseudo-Riemannian homogeneous spaces Author: Kazuki Kannaka, Toshiyuki Kobayashi arXiv: http://arxiv.org/abs/2507.03476v1 Title: Whole-genome ancestry of an Old Kingdom Egyptian Author: Adeline Morez Jacobs, Joel D. Irish, Ashley Cooke, Kyriaki Anastasiadou, Christopher Barrington, Alexandre Gilardet, Monica Kelly, Marina Silva, Leo Speidel, Frankie Tait, Mia Williams, Nicolas Brucato, Francois-Xavier Ricaut, Caroline Wilkinson, Richard Madgwick, Emily Holt, Alexandra J. Nederbragt, Edward Inglis, Mateja Hajdinjak, Pontus Skoglund, Linus Girdland-Flink Journal Reference: Nature 2025 doi: https://doi.org/10.1038/s41586-025-09195-5
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2025-07-10
Press Release
Capturing the Echoes of Black Holes with Mathematical Precision
A research group including Ryo Namba (Senior Research Scientist, iTHEMS) has successfully demonstrated a method that systematically and precisely captures the frequency structure of rapidly decaying quasinormal modes of black holes by incorporating the mathematical technique known as exact WKB analysis. This result enables more rigorous analysis of gravitational wave signals from black holes in various theoretical models and is expected to contribute to improving the precision of future gravitational wave observations and verifying the fundamental properties of black holes with greater accuracy. For further details, please refer to the related link below.
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2025-07-09
Person of the Week
Self-introduction: Zhe Wang
I received my doctoral degree from Tsinghua University in 2023. After that, I spent two years at Kyoto University as a postdoctoral researcher. In 2025, I joined iTHEMS. My main research interest lies in exploring various aspects of mathematical physics using tools from integrable systems. In particular, I apply techniques from (infinite-dimensional) Hamiltonian integrable systems to study Gromov-Witten type theories, mirror symmetry, and related topics. A typical problem in this area involves constructing integrable systems that govern the partition functions of specific theories—such as cohomological field theory, equivariant quantum cohomology, quantum K-theory, or symplectic field theory—and analyzing their structure through the integrable systems. More recently, I've become increasingly interested in the connections between integrable hierarchies and quantum algebras, such as vertex algebras and W-algebras. While the classical relationships between these fields have been well studied, understanding their quantum counterparts remains a rich and challenging direction. I believe that further progress in this area will deepen our overall understanding of integrable systems, which play a central role in mathematical physics. If you’re interested in my work or would like to discuss related topics, I’d be very happy to hear from you. Please feel free to reach out!
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2025-07-08
Research News
RIKEN NEWS: The Appeal of the ECL Program in Nurturing Early-Career Researchers
An interview with Leo Speidel (RIKEN ECL Research Unit Leader, Mathematical Genomics RIKEN ECL Research Unit) has been featured in the Topics section, as part of the Close-up RIKEN 2025 series on RIKEN’s research introduction page. A video interview is also available alongside the article. The RIKEN Early Career Leaders (ECL) Program was launched in 2023 to provide more substantial support for early-career researchers. Building on and expanding the previous RIKEN Hakubi Program, the ECL Program enables researchers to pursue agile and flexible research. In addition to appointing Team Leaders (equivalent to department heads or young professors at universities), the program has introduced the position of Unit Leader (equivalent to section heads or associate professors/lecturers at universities) to support outstanding young researchers with limited experience. These Unit Leaders are provided with a highly mobile and independent research environment at their host research centers. We spoke with Dr. Leo Speidel, the RIKEN ECL Research Unit Leader of the Mathematical Genomics RIKEN ECL Research Unit, Mathematical Science Core Division, at the Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS), who is part of the program's first cohort. He is working to uncover human evolution and history through the study of DNA mutations, and he shared with us the appeal of the ECL Program. For more information, please see the related links below.
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2025-07-03
Press Release
Using viral load tests to help predict mpox severity when skin lesions first appear
A research group led by Shingo Iwami (Visiting Scientist, iTHEMS) has revealed through an international collaborative study that there is significant individual variation in the progression of skin lesions among patients infected with mpox (Clade Ia). The study also suggests that the blood viral load at the time of onset may serve as a useful indicator for predicting the progression of these symptoms. For more details, please refer to the related links.
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2025-07-03
Paper of the WeekWeek 1, July 2025
Title: Susceptibilities of rotating quark matter in Fourier-Bessel basis Author: Mamiya Kawaguchi, Kazuya Mameda arXiv: http://arxiv.org/abs/2507.00494v1 Title: Topological Defect Propagation to Classify Knitted Fabrics Author: Daisuke S. Shimamoto, Keiko Shimamoto, Sonia Mahmoudi, Samuel Poincloux arXiv: http://arxiv.org/abs/2506.22369v1 Title: Universal framework with exponential speedup for the quantum simulation of quantum field theories including QCD Author: Jad C. Halimeh, Masanori Hanada, Shunji Matsuura arXiv: http://arxiv.org/abs/2506.18966v1 Title: Observation of entanglement in a cold atom analog of cosmological preheating Author: Victor Gondret, Clothilde Lamirault, Rui Dias, Léa Camier, Amaury Micheli, Charlie Leprince, Quentin Marolleau, Jean-René Rullier, Scott Robertson, Denis Boiron, Christoph I. Westbrook arXiv: http://arxiv.org/abs/2506.22024v1
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2025-07-03
Press Release
A New Intelligence Deciphering the Universe: Discovery of Anomalous Energy Emission Phenomena through Quantum × AI
A research group, including Shigehiro Nagataki (Chief Scientist, Astrophysical Big Bang Laboratory, RIKEN PRI / Deputy Director, iTHEMS) and Shunji Matsuura (Senior Research Scientist, iTHEMS), has successfully detected 113 anomalous energy (X-ray) emission events. This was achieved by constructing and applying a quantum machine learning model that integrates quantum computing with machine learning to a large-scale dataset of X-ray variability in space accumulated over approximately 24 years by the X-ray astronomical satellite XMM-Newton, operated by the European Space Agency (ESA). For more information, please refer to the related links below.
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2025-07-03
Hot Topic
Farewell message from Yuki Fujimoto
Our colleague, Yuki Fujimoto, left iTHEMS on June 30 and has moved to Niigata University to take up a position as Assistant Professor. We thank him for his time at iTHEMS and wish him all the best in this new chapter. Here is a message from Yuki Fujimoto: As of June 30, I have left iTHEMS, and I would like to express my sincere gratitude to all the members of iTHEMS. I am moving to Niigata University to take up a position as an assistant professor. I joined iTHEMS in October 2024 as a RIKEN-Berkeley Fellow and was primarily based at the RIKEN center at UC Berkeley. Although my time at the Wako campus was brief, I greatly enjoyed the interactions and discussions with colleagues from a wide range of fields. I will continue to be affiliated with iTHEMS as a visiting scholar, and I look forward to seeing you all when I visit Wako. You are all very welcome to visit me in Niigata as well. I wish iTHEMS continued growth and success in the future.
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2025-07-03
Press ReleaseTheoretical Discovery of Angular Momentum Reversal in Magnetic Vortical Matter
A collaborative research group, including Kazuya Mameda (Visiting Scientist, iTHEMS) has theoretically discovered that in quantum systems where strong magnetic fields and rotation coexist, the polarization of angular momentum becomes dominated by orbital angular momentum—originating from the particles’ orbital motion—rather than spin. This leads to a reversed direction of polarization compared to conventional expectations. For more information, please refer to the related links below.
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2025-07-03
Press Release
AI-Driven High-Resolution Galaxy Simulations: Accelerating Galaxy Evolution Modeling from 8 Months to 2
An international collaborative research group, including Keiya Hirashima (Special Postdoctoral Researcher, iTHEMS), has developed a surrogate model using deep learning, a form of artificial intelligence (AI), to predict the complex physical processes of supernova explosions. This model has been integrated into a galaxy simulation code for the first time. This achievement marks the first instance of accelerating high-resolution "star-by-star" galaxy simulations by performing deep learning inference in real time during the simulation—something that was previously difficult to realize. The new method is expected to contribute to detailed analysis of supernova feedback in the formation and evolution of our own Milky Way galaxy. For more information, please refer to the related links below.
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2025-06-26
Paper of the WeekWeek 5, June 2025
Title: A new upper bound for mutually touching infinite cylinders Author: Junnosuke Koizumi arXiv: http://arxiv.org/abs/2506.19309v1 Title: The quantum criticality of the Standard Model and the hierarchy problem Author: Juan P. Garcés, Florian Goertz, Manfred Lindner, Álvaro Pastor-Gutiérrez arXiv: http://arxiv.org/abs/2506.15919v1 Title: Observing Leptogenesis in Action with Gravitational Waves Author: Hitoshi Murayama, Bea Noether, Jan Schütte-Engel arXiv: http://arxiv.org/abs/2506.15772v1
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2025-06-23
Press Release
Bulk-Edge Correspondence of Measurement-Induced Topological Phases
A research group including Ryusuke Hamazaki (Senior Research Scientist, iTHEMS) has proposed a method to investigate the effective energy level structures and bulk topological invariants in quantum systems under measurement. Utilizing this approach, the team conducted a theoretical analysis of topological phase transitions induced by quantum measurements. Their findings revealed that zero-energy edge states originating from so-called "Majorana particles" can emerge in topological phases under continuous measurement. Furthermore, the study demonstrated that the bulk-edge correspondence, a universal principle typically known to hold in isolated quantum systems, also manifests in measurement-driven quantum systems. This work establishes a robust theoretical foundation for measurement-induced topological phase transitions. The method developed is broadly applicable to a wide class of topological phases, offering a versatile tool that may lead to a systematic and unified understanding of quantum phases induced by measurement. For more details, please refer to the related links.
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2025-06-23
Press Release
Success in Quantum Chemistry Calculations through Quantum–Supercomputer Collaboration
An international research team, including Senior Research Scientist Tomonori Shirakawa, has demonstrated the practical potential of quantum computing by performing calculations that combine IBM's quantum computer with RIKEN's supercomputer "Fugaku" to address quantum chemistry problems that have been difficult to analyze using conventional classical computers. In this study, by processing output data obtained from a real quantum computer with a supercomputer, the team successfully obtained scientifically meaningful results for a large-scale quantum chemical system exceeding 50 qubits for the first time. This achievement demonstrates that quantum computing is effective even for quantum chemistry problems that surpass the limitations of classical computation, marking a significant step forward toward the practical application of quantum computing. For more details, please refer to the related links.
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2025-06-23
Research News
RIKEN NEWS: A New World Unlocked by a Data Geek
An interview with Catherine Beauchemin (Deputy Director, iTHEMS) has been featured in the RIKEN People section, as part of the Close-up RIKEN 2025 series on RIKEN’s research introduction page. With her quick wit, rapid-fire speech, and warm smile, she embodies the charm and potential of what it means to be human. Dr. Beauchemin is pioneering a new research field known as “virus physics.” By applying the tools of physics, she investigates viruses, unseen entities that can pose serious threats to our lives. To read the full story, please see the related link below.
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2025-06-19
Paper of the WeekWeek 4, June 2025
Title: On 3-periodic tangled networks and their untangling number Author: Toky Andriamanalina, Sonia Mahmoudi, Myfanwy E. Evans arXiv: http://arxiv.org/abs/2506.15252v1 Title: Quantitative predictions of alpha-charmonium correlation functions in high-energy collisions Author: Faisal Etminan arXiv: http://arxiv.org/abs/2506.14724v1 Title: Enhancement of axial anomaly effects in hot two-color QCD: FRG approach in the linear sigma model Author: Gergely Fejős, Daiki Suenaga arXiv: http://arxiv.org/abs/2506.14010v1 Title: Scalable Simulation of Quantum Many-Body Dynamics with Or-Represented Quantum Algebra Author: Lukas Broers, Rong-Yang Sun, Seiji Yunoki arXiv: http://arxiv.org/abs/2506.13241v1 Title: Unpolarized prethermal discrete time crystal Author: Takeru Yokota, Tatsuhiko N. Ikeda arXiv: http://arxiv.org/abs/2501.09461v2 Title: Schwinger-Keldysh approach to tunneling transport at a hadron-quark interface Author: Tingyu Zhang, Hiroyuki Tajima, Motoi Tachibana arXiv: http://arxiv.org/abs/2506.09725v1
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2025-06-12
Person of the Week
Self-introduction: Keiya Hirashima
Hi! My name is Keiya Hirashima, and I am a Special Postdoctoral Researcher at iTHEMS, working on galaxy formation and evolution using AI and large-scale simulations. My research focuses on modeling the effects of individual stars and stellar feedback in high-resolution galaxy simulations. To reduce computational costs, I have developed AI-based surrogate models that efficiently replace expensive physical simulations. I’m particularly interested in connecting different physical scales to study the hierarchical evolution of galaxies and the universe through numerical methods, deep learning, and high-performance computing. I also explore how fractal structures and foundation models can help extract general representations from complex physical systems. [My academic history] I began my position as a Special Postdoctoral Researcher at iTHEMS in April 2025. Prior to that, I studied computer science and mathematical science at Kyoto University in March 2020, and received my Ph.D. in Astronomy (sub: Information Science) from the University of Tokyo in March 2025. I have also worked on research on deep foundation models for (astro)physics at PolymathicAI and Flatiron Institute (USA).
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2025-06-12
Paper of the WeekWeek 3, June 2025
Title: Charge symmetry breaking effects of $ω$-$ρ^0$ mixing in relativistic mean-field model Author: Yusuke Tanimura, Tomoya Naito, Hiroyuki Sagawa, Myung-Ki Cheoun arXiv: http://arxiv.org/abs/2506.06629v1 Title: Revealing long-term multi-factor climate impacts on antarctic phytoplankton: a trend-based approach using STL and piecewise SEM Author: Hitomi Tanaka, Hideyuki Doi, Ryosuke Iritani Journal Reference: bioRxiv doi: https://doi.org/10.1101/2025.06.03.657605 Title: Free Probability approach to spectral and operator statistics in Rosenzweig-Porter random matrix ensembles Author: Viktor Jahnke, Pratik Nandy, Kuntal Pal, Hugo A. Camargo, Keun-Young Kim arXiv: http://arxiv.org/abs/2506.04520v1
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2025-06-12
Press Release
Developing a framework for inferring spatial biodiversity: quantifying the "beta-diversity" patterns
An international research team led by Ryosuke Iritani, Senior Research Scientist at RIKEN iTHEMS, has developed a theoretical framework to estimate the probability distribution of spatial biodiversity. This interdisciplinary work uses fuzzy set theory to formulate species presence-absence in a community, armed with analytical techniques and concepts from mathematics and theoretical physics. This work enables a quantitative assessment of differences and variations in species richness across regions, contributing to the prediction of how environmental changes in the biosphere influence biodiversity. For more details, please refer to the related link.
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2025-06-12
Person of the Week
Self-introduction: Robert Baird
Hi, I'm Robert Baird. I'm from the UK and completed my undergraduate degree Zoology at the University of Sheffield, followed by a Masters in Biology at LMU Munich in Germany. I then completed my PhD in Evolutionary Biology at the University of Edinburgh. I'm currently a postdoctoral scientist at the Whitehead Institute for Biomedical Science at MIT, where I combine cytology with evolution to understand species with unusual genetics and what this can tell us about more fundamental biological questions. I am a visiting researcher at iTHEMS, working with Thomas Hitchcock to try to develop ideas and predictions for how some of the unusual genetic systems that I study evolved.
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2025-06-12
Seminar Report
iTHEMS Theoretical Physics Seminar by Wu Xianxin on June 5, 2025
On June 5, Prof. Xianxin Wu (the Institute of theoretical Physics, Chinese Academy of Sciences) delivered a seminar hosted by RIKEN iTHEMS, where he presented an overview of recent experimental advances in kagome metals. His talk highlighted key phenomena such as unconventional superconductivity, charge density wave (CDW) order, and electronic nematicity. Particularly noteworthy was the growing body of evidence indicating spontaneous time-reversal symmetry (TRS) breaking within the CDW phase—potentially signaling the emergence of a long-sought loop current order, although its microscopic origin remains unresolved. Following this overview, he discussed an effective theoretical model that captures the unique sublattice texture associated with van Hove singularities in the kagome lattice. This sublattice structure plays a crucial role in shaping correlated electronic states. To conclude the seminar, Xianxin proposed a theoretical scenario for the emergence of a TRS-breaking CDW in kagome systems and explored the possibility of unconventional superconducting pairing mediated by loop-current fluctuations. Reported by Ching-Kai Chiu and Congcong Le
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2025-06-05
Paper of the WeekWeek 2, June 2025
Title: Insights in $f(Q)$ cosmology: the relevance of the connection Author: Ismael Ayuso, Mariam Bouhmadi-López, Che-Yu Chen, Xiao Yan Chew, Konstantinos Dialektopoulos, Yen Chin Ong arXiv: http://arxiv.org/abs/2506.03506v1 Title: Anomaly of conserved and nonconserved axial charges in Hamiltonian lattice gauge theory Author: Yoshimasa Hidaka, Arata Yamamoto arXiv: http://arxiv.org/abs/2506.01336v1 Title: A New State of Matter between the Hadronic Phase and the Quark-Gluon Plasma? Author: Yuki Fujimoto, Kenji Fukushima, Yoshimasa Hidaka, Larry McLerran arXiv: http://arxiv.org/abs/2506.00237v1 Title: Asteroseismology and Universal Relations in Neutron Stars with Gravitationally Bound Dark Matter Author: Ankit Kumar, Hajime Sotani arXiv: http://arxiv.org/abs/2506.00311v1 Title: Monte Carlo simulations of relativistic shock breakout from a stellar wind Author: Hirotaka Ito, Amir Levinson, Ehud Nakar, Shigehiro Nagataki arXiv: http://arxiv.org/abs/2506.01398v1 Title: Prehistoric genomes from Yunnan reveal ancestry related to Tibetans and Austroasiatic speakers Author: Tianyi Wang, Melinda A. Yang, Zhonghua Zhu, Minmin Ma, Han Shi, Leo Speidel, Rui Min, ..., Mark Stoneking, Qiaomei Fu Journal Reference: Science 388, eadq9792 (2025) doi: https://doi.org/10.1126/science.adq9792 Title: Ancient Borrelia genomes document the evolutionary history of louse-borne relapsing fever Author: Pooja Swali, Thomas Booth, Cedric C. S. Tan, Jesse McCabe, Kyriaki Anastasiadou, Christopher Barrington, Matteo Borrini, Adelle Bricking, Jo Buckberry, Lindsey Büster, Rea Carlin, Alexandre Gilardet, Isabelle Glocke, Joel D. Irish, Monica Kelly, Megan King, Fiona Petchey, Jessica Peto, Marina Silva, Leo Speidel, Frankie Tait, Adelina Teoaca, Satu Valoriani, Mia Williams, Richard Madgwick, Graham Mullan, Linda Wilson, Kevin Cootes, Ian Armit, Maximiliano G. Gutierrez, Lucy van Dorp, and Pontus Skoglund Journal Reference: Science 388, eadr2147 (2025) doi: https://doi.org/10.1126/science.adr2147 Title: High-resolution genomic history of early medieval Europe Author: Leo Speidel, Marina Silva, Thomas Booth, Ben Raffield, Kyriaki Anastasiadou, Christopher Barrington, Anders Götherström, Peter Heather & Pontus Skoglund Journal Reference: Nature 637, 118–126 (2025) doi: https://doi.org/10.1038/s41586-024-08275-2
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2025-06-05
Award
Kenji Fukaya Wins 2025 Shaw Prize in Mathematical Sciences
Our iTHEMS former colleague, Kenji Fukaya, has been awarded the 2025 Shaw Prize in Mathematical Sciences" for his pioneering work on symplectic geometry, especially for envisioning the existence of a category — nowadays called the Fukaya category — consisting of Lagrangians on a symplectic manifold, for leading the monumental task of constructing it, and for his subsequent ground-breaking and impactful contributions to symplectic topology, mirror symmetry, and gauge theory.” Congratulations, Kenji!
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2025-06-04
Person of the Week
Self-introduction: Antoine Diez
Hello! I am interested in the mathematical modeling of large scale self-organized phe- nomena in life science, from the dynamics of biological cells forming tissues to the behaviour of interacting agents within societies. These systems, often referred to as complex systems, are typically described as large systems of active particles. Their understanding mostly relies on the derivation and analysis of suitable scaling limits that reveal more informative statistical descriptors. My background is in mathematical kinetic theory, a branch of statistical physics originally developed to bridge the gap between molecular-level gas dynamics and macroscopic thermodynamic and fluid equations. My work combines analytical approaches (in particular partial differential equations, stochastic analysis and a bit of geometry) but also in silico computer simulations that are nowdays essential. I am interested in theoretical mathematical problems but I also work in close collaboration with biologists on interdisciplinary applied projects, especially in developmental biology.
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2025-06-04
Person of the Week
Self-introduction: Unashish Mondal
Hey everyone, I’m Unashish Mondal. I joined iTHEMS and the Prediction Science Research Team as a postdoctoral researcher, with a strong interest in extreme weather events and their underlying dynamics. My research primarily focuses on understanding and predicting lightning, thunderstorms, and associated hazards across the Indian subcontinent, using a combination of satellite observations, reanalysis data, and advanced modelling techniques. I’ve also worked extensively with the Weather Research and Forecasting (WRF) model to simulate cloudbursts, hailstorms, and heatwaves over India, integrating high-resolution simulations with observational analysis. I’m passionate about advancing the prediction of extreme events through data assimilation, machine learning, and high-resolution modelling—especially in data-sparse and climate-vulnerable regions. Outside of research, I enjoy reading books, traveling, and discussing philosophy and culture.
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2025-06-04
Featured Paper of the Week
Understanding dynamics and quantum chaos through Krylov space
In everyday life, we often associate chaos with randomness, disorder, or unpredictability—phenomena that appear to lack any discernible pattern. However, from a physics standpoint, understanding chaos requires a more rigorous and precise mathematical framework. In classical physics, chaos is often perceived through its sensitive dependence on initial conditions. Small perturbations in an initial state of a system can lead to vastly different outcomes over time, a behavior commonly known as “butterfly effect”, and typically analyzed within the framework of phase space trajectories, and its detailed topological properties. In contrast, chaos in the quantum realm presents unique challenges. The notion of sharp trajectories in phase space clashes with Heisenberg’s uncertainty principle in quantum mechanics, and initial perturbations cannot be treated in a way that mirrors classical intuition. As a result, quantum chaos requires distinct formulations, relying on diagnostic tools like spectral statistics, out-of-time-order correlators, and entanglement measures. However, the relationships between these different probes are not always clear, and a unified understanding remains an open area of research. In recent years, significant progress has been made in understanding quantum chaos through the lens of operator growth, where localized quantum information encoded in simple operators spreads across a system—a process known as information scrambling. Such phenomena is crucial in understanding the thermalization of a system. Krylov space, a subspace of the operator Hilbert space, provides an elegant framework to describe such operator growth. By decomposing operator dynamics using an orthonormal basis, it traces how simple operators evolve into increasingly complex ones—quantified by a complexity measure in Krylov space. A parallel formulation exists for the evolution of quantum states, offering a complementary perspective. Importantly, to make these ideas applicable to realistic physical scenarios, one must consider open quantum systems—systems that interact with their environment. In such contexts, the dynamics become richer, requiring more generic theoretical and computational techniques. Furthermore, efficient quantum control protocols often leverage the structured Hilbert space, with Krylov subspace methods providing computationally efficient frameworks. These methods facilitate guiding systems along desired adiabatic trajectories, reducing runtime and mitigating decoherence effects, as often required for quantum technologies. These developments form the core focus of this review article.
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2025-06-03
Press Release
Information entropy untangles vortices and flows in turbulent plasmas: A turbulence analysis inspired by quantum information theory
A research team including Motoki Nakata (Visiting Scientist, iTHEMS) has proposed a novel method that interprets structural transitions and nonlinear interactions in turbulent fields from the perspective of “information,” inspired from information entropy and its mathematical formalism used in quantum mechanics theory. This approach has enabled the discovery of new turbulent states in plasma—states that had been overlooked by conventional energy-based analysis methods—and the extraction of key interactions among vortices and flows in various scales. The team also proposes an application of this method to experimental measurements that observe turbulence and fluctuations. Looking ahead, this technique is expected to be applied beyond turbulent plasmas to a wide range of research domains involving “complex flows” and “mutually correlated fluctuations,” appearing in atmospheric, oceanic, and social systems. For more details, please refer to the press release available through the related links.
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2025-05-30
Person of the Week
Self-introduction: Vladimir Sosnilo
Hi all, my name is Vladimir (Vova) Sosnilo. I am a mathematician working in the fields of category theory, homotopy theory, and algebraic geometry. Category theory studies abstract relations between mathematical objects. In a precise mathematical sense, the Yoneda Lemma asserts that a given (mathematical) object is determined by its relations to other objects. While this means that any mathematical phenomenon can, in principle, be understood from the perspective of category theory, these relations can be incredibly intricate. The main idea unifying most of my work is the existence of simple categorical patterns that show up across many different areas of mathematics. This can be used to understand concrete objects in geometry and representation theory. I am originally from Saint Petersburg, Russia, but I also spent a significant amount of time in Germany before coming to iTHEMS. In particular, I did a three-year postdoc at the University of Regensburg. Beyond research, I am interested in music and arts. You can find more about me on my webpage or by talking to me!
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2025-05-29
Paper of the WeekWeek 5, May 2025
Title: Incorporating episodic memory into quantum models of judgment and decision Author: Jerome R. Busemeyer, Masanao Ozawa, Emmanuel M. Pothos, Naotsugu Tsuchiya arXiv: http://arxiv.org/abs/2505.21521v1 Title: Nonperturbative Quantum Gravity in a Closed Lorentzian Universe Author: Yasunori Nomura, Tomonori Ugajin arXiv: http://arxiv.org/abs/2505.20390v1 Title: Parametrized Tidal Dissipation Numbers of Non-rotating Black Holes Author: Hajime Kobayashi, Shinji Mukohyama, Naritaka Oshita, Kazufumi Takahashi, Vicharit Yingcharoenrat arXiv: http://arxiv.org/abs/2505.19725v1 Title: Notes on Rindler wave packets in Minkowski spacetime Author: Shono Shibuya, Sotaro Sugishita arXiv: http://arxiv.org/abs/2505.20078v1 Title: Emergence of new oscillation modes in dark matter admixed neutron stars Author: Hajime Sotani, Ankit Kumar arXiv: http://arxiv.org/abs/2505.18800v1 Title: Time-dependent Hole States in Multiconfigurational Time-Dependent Hartree-Fock Approaches: Applications in Photoionization of Water Molecule Author: Zhao-Han Zhang, Yang Li, Himadri Pathak, Takeshi Sato, Kenichi L. Ishikawa, Feng He arXiv: http://arxiv.org/abs/2505.11319v1 Title: Time-dependent Hole States in Multiconfigurational Time-Dependent Hartree-Fock Approaches: A Time-Domain Generalization of Extended Koopmans' Theorem Author: Zhao-Han Zhang, Yang Li, Himadri Pathak, Takeshi Sato, Kenichi L. Ishikawa, Feng He arXiv: http://arxiv.org/abs/2505.11290v1
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2025-05-27
Seminar Report
iTHEMS Theoretical Physics Seminar by Masashi Kawahira on May 27, 2025
On May 27, Mr. Masashi Kawahira gave a seminar hosted by RIKEN iTHEMS. His talk focused on generalized symmetry and quantum symmetry from Type IIB superstring theory. Recently, generalized symmetries have enabled the systematic analysis of various quantum systems. He discussed global generalized symmetries that appear in the low-energy effective theory of type IIB superstring theory, specifically type IIB supergravity. Specifically, his work is related to the SL(2,ℤ) gauge symmetry (self-duality) in type IIB supergravity. He demonstrated that a global ℤ₁₂ eight-form symmetry emerges as the quantum symmetry of the SL(2,ℤ) gauge symmetry, along with its topological operator and its connection to 7-branes. Reported by Okuto Morikawa
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