News
102 news in 2025
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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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2025-05-26
Person of the Week
Self-introduction: Chi-Kang Chang
My research field is algebraic geometry, with a particular focus on birational geometry. Before joining RIKEN iTHEMS, I was a postdoctoral researcher at the National Center for Theoretical Sciences (NCTS) in Taiwan for about nine months. I completed all of my undergraduate, master's, and doctoral studies in the Department of Mathematics at National Taiwan University. During my doctoral studies, I also spent about 14 months as a visiting research associate at the Graduate School of Mathematical Sciences, the University of Tokyo.
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2025-05-26
Seminar Report
Quantum Computation SG Seminar by Alberto Nocera on May 23, 2025
On May 23, 2025, the Quantum Computation Study Group hosted a seminar featuring Dr. Alberto Nocera, an author on the recent Science publication that propelled D-Wave’s quantum annealer into the international spotlight. This event was held online and attracted approximately 30 participants, who engaged actively throughout the session. Dr. Nocera delivered a highly pedagogical talk introducing the D-Wave quantum annealer and its unique approach to quantum simulation. One of the highlights of his presentation was a clear explanation of why, given the short coherence time in D-Wave’s devices, quantum states cannot adiabatically evolve. Instead, a quench of the quantum states is essential, which presents major simulation challenges for classical computers—especially at large scales. In contrast, D-Wave’s quantum annealer demonstrates the capacity to efficiently scale up such quantum quenches. The seminar was highly interactive, with numerous questions raised both during and after the presentation. The lively Q&A underscored the community’s keen interest in the future of quantum simulation and the practical capabilities of current quantum hardware. Overall, Dr. Nocera’s talk provided valuable insights into the rapidly evolving landscape of quantum computation and demonstrated the vital role of quantum annealers in tackling problems beyond the reach of classical computing. Reported by Ching-Kai Chiu and Shunji Matsuura
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2025-05-22
Researches & Researchers
International and Interdisciplinary Collaboration at the RIKEN-Berkeley Center - Yuuka Kanakubo
"I’m leaving for the U.S. tomorrow," says Yuuka Kanakubo, who joined iTHEMS in October 2024 as a Postdoctoral Researcher and RIKEN-Berkeley Fellow. Her specialty is elementary particle and nuclear theory. She will be conducting research during a long-term stay at the RIKEN-Berkeley Center, iTHEMS' satellite office. "This position is perfect for me," Kanakubo says. We asked her about her journey so far and what makes this opportunity ideal. Please see the full article via the related link.
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2025-05-22
Award
Yoshimasa Hidaka received the 25th Soryushi Medal for his unified description of the Nambu-Goldstone theorem
Yoshimasa Hidaka, our Deputy Director, is awarded 25th SORYUSHI MEDAL (Paricle Physics Medal) from Japanese Particle Theory Community. The title of the achievement is “Unified Description of the Nambu-Goldstone Theorem”. The award will be presented at the 80th Annual Meeting of the Physical Society of Japan, to be held at Hiroshima University from September 16 to 19, 2025. Congratulations!!
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2025-05-22
Paper of the WeekWeek 4, May 2025
Title: Quasinormal Modes from EFT of Black Hole Perturbations in Vector-Tensor Gravity Author: Shogo Tomizuka, Hajime Kobayashi, Naritaka Oshita, Kazufumi Takahashi, Shinji Mukohyama arXiv: http://arxiv.org/abs/2505.15125v1 Title: Cobordism maps in Khovanov homology and singular instanton homology I Author: Hayato Imori, Taketo Sano, Kouki Sato, Masaki Taniguchi arXiv: http://arxiv.org/abs/2505.12095v1 Title: Using inclusive fitness and eco-evolutionary theory to model cultural evolution Author: Ryosuke Iritani, Stuart A West Journal Reference: Evolution and Human Behavior 46 (2025) doi: https://doi.org/10.1016/j.evolhumbehav.2025.106693 Title: The evolution of host utilization strategy: At what timing parasitoids attack and consume their host Author: Ryuichiro Isshiki, Ryosuke Iritani Journal Reference: bioRxiv doi: https://doi.org/10.1101/2025.02.22.639661 Title: How can interspecific pollen transfer affect the coevolution and coexistence of two closely related plant species? Author: Keiichi Morita, Akira Sasaki, Ryosuke Iritani Journal Reference: OIKOS e11133 (2025) doi: https://doi.org/10.1002/oik.11133 Title: An Analytic Prescription for $t$-channel Singularities Author: Kento Asai, Nagisa Hiroshima, Joe Sato, Ryusei Sato, Masaki J. S. Yang arXiv: http://arxiv.org/abs/2505.10890v1 Title: Landscape of Correlated Orders in Strained Bilayer Nickelate Thin Films Author: Congcong Le, Jun Zhan, Xianxin Wu, Jiangping Hu arXiv: http://arxiv.org/abs/2501.14665v2
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2025-05-22
Award
Haruki Emori received the “Second Prize”
Our colleague Haruki Emori (Junior Research Associate, iTHEMS) has received the “Second Prize’” in the Poster Session for the Quantinuum 2025 May Training Session. The outstanding presentation poster is entitled “Quantum algorithm for implementing arbitrary quantum instruments based on parameterized quantum circuits”. Congratulations, Haruki!
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2025-05-22
Seminar Report
Report on the seminar “Universality class for driven interfaces and... integrable spin hydrodynamics?” by Kazumasa A. Takeuchi on May 19, 2025
On 19 May 2025, Professor Kazumasa A. Takeuchi (Univ. of Tokyo) gave an iTHEMS hybrid seminar, “Universality class for driven interfaces and… integrable spin hydrodynamics?” He first gave a review of the one-dimensional KPZ universality class, highlighting exact Tracy–Widom statistics, geometry-dependent subclasses, and elegant experiments with electrically driven nematic-liquid-crystal fronts. A “KPZ Huygens principle” was proposed to unify these results. He then unveiled a recent surprise: equilibrium fluctuations of isotropic integrable spin chains display KPZ-type scaling. Two-point correlations match KPZ predictions, though non-2pt quantities are totally different. Approximately 60 participants, including those on Zoom, attended the seminar, and the Q&A session was lively and engaging. Reported by Yoshimasa Hidaka
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2025-05-20
Researches & Researchers
Looking for “Overlap” to Connect - Akihisa Yamamoto
"I have always walked along the boundaries between different fields," says Research Scientist Akihisa Yamamoto. Currently, he is focusing on the interdisciplinary field between medicine and mathematics, seeking to identify patterns in doctors' experiential knowledge, translating them into mathematical models, and applying them to deepen our understanding of biological phenomena while contributing to clinical practice. We spoke with him about the encounters that led him to this path, as well as the unique challenges and excitement of working at the intersection of disciplines. Please see the full article via the related link.
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2025-05-15
Paper of the WeekWeek 3, May 2025
Title: Exponential improvement in quantum simulations of bosons Author: Masanori Hanada, Shunji Matsuura, Emanuele Mendicelli, Enrico Rinaldi arXiv: http://arxiv.org/abs/2505.02553v2 Title: A novel view of the flavor-singlet spectrum from multi-flavor QCD on the lattice Author: Yasumichi Aoki, Tatsumi Aoyama, Ed Bennett, Toshihide Maskawa, Kohtaroh Miura, Hiroshi Ohki, Enrico Rinaldi, Akihiro Shibata, Koichi Yamawaki, Takeshi Yamazaki arXiv: http://arxiv.org/abs/2505.08658v1 Title: Bubble formation in active binary mixture model Author: Kyosuke Adachi arXiv: http://arxiv.org/abs/2505.08637v1 Title: On the validity of the complex Langevin method near the deconfining phase transition in QCD at finite density Author: Shoichiro Tsutsui, Yuhma Asano, Yuta Ito, Hideo Matsufuru, Yusuke Namekawa, Jun Nishimura, Shinji Shimasaki, Asato Tsuchiya arXiv: http://arxiv.org/abs/2505.06551v1 Title: Enhancement of photon emission rate near QCD critical point Author: Yukinao Akamatsu, Masayuki Asakawa, Masaru Hongo, Mikhail Stephanov, Ho-Ung Yee arXiv: http://arxiv.org/abs/2505.07169v1 Title: The Moon as a Cosmic-Ray Spectrometer: Prospects for MeV Gamma-Ray Observations Author: Tatsuki Fujiwara, Ellis R. Owen, Yoshiyuki Inoue, Manel Errando, Kohei Fukuda, Kazuhiro Nakazawa, Hirokazu Odaka, Keigo Okuma, Kentaro Terada, Naomi Tsuji, Yasunobu Uchiyama, Hiroki Yoneda, Ao Zhang arXiv: http://arxiv.org/abs/2504.07195v2
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2025-05-15
Researches & Researchers
Utilizing Every Possible Method to Challenge the Ultimate Goal - Masazumi Honda
What are the fundamental building blocks of the universe? What is the ultimate physical law that govern the universe? How did the universe begin? Theoretical high energy physics, which seeks to answer these profound questions, is the main research field for Masazumi Honda. We spoke with Honda about his journey to iTHEMS, the breadth of his research approaches and disciplines, and his recent research on applying quantum computers to high energy physics. Please see the full article via the related link.
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2025-05-14
Person of the Week
Self-introduction: Shuntaro Aoki
Hello, My name is Shuntaro Aoki, and I am a researcher at RIKEN iTHEMS. My primary areas of expertise are particle physics and cosmology, with a special focus on the early universe. I obtained my PhD from Waseda University in 2018 and worked as a lecturer at the same institution until March 2021. In April 2021, I joined Chung-Ang University in Korea, where I worked until August 2022. Subsequently, I continued my research at the Institute for Basic Science (Korea) until November 2024, before joining RIKEN iTHEMS in December 2024. My current research focuses on the cosmological collider program, which aims to uncover new physics beyond the Standard Model through the study of non-Gaussianity in primordial perturbations. These perturbations, believed to have been generated in the early universe at extremely high energies, provide valuable insights into heavy particles that are inaccessible in terrestrial experiments. Specifically, I have been working on the theoretical aspects of the cosmological collider, such as deriving analytic expressions for correlation functions and exploring particle physics models that predict large "signals" of interest. This research lies at the intersection of cosmology and particle physics, offering exciting implications for both fields. My long-term goal is to contribute to uncovering high-energy physics through cosmological observations. Ultimately, I aim to deepen our understanding of the universe's fundamental nature and its origins, while fostering new methodologies and collaborative efforts to advance the field. Beyond research, I enjoy football, fishing, and walking—activities that help me maintain a balanced and creative approach to problem-solving.
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2025-05-14
Person of the Week
Self-introduction: Iao-Fai Io
Hello everyone, my name is Iao-Fai Io, you can call me Jacky (my nickname). I am a Ph.D. student at National Taiwan University (NTU) and also an IPA student at RIKEN iTHEMS. Although I study in Taiwan, I am originally from Macau, so I know how to speak cantonese and mandarin My research direction is condensed matter physics, specifically focusing on non-Hermitian systems, particularly one-dimensional lattice models (e.g., the SSH model and its extended versions). Currently, I am studying conformal symmetry in 1+1D non-Hermitian systems, including both lattice models and field theory, to understand the differences between Hermitian and non-Hermitian cases and to explore new physics in non-Hermitian systems. I am also interested in other topics in condensed matter theory, including topological insulators and superconductors.
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2025-05-13
Person of the Week
Self-introduction: Daichi Takeda
My name is Daichi Takeda. I was born in Himeji (Hyōgo Prefecture), and have also lived in Fujisawa (Kanagawa) and Kyoto (Kyoto). I spent nine years at Kyoto University — from my undergraduate studies through my doctoral program — and received a Ph.D. in Science in March 2024. My field is theoretical high energy physics, with a focus on exploring the microscopic theory of gravity. Recently, I have been investigating the properties of black holes and methods for conducting virtual gravity experiments in a laboratory setting, with the help of the holographic principle.
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2025-05-13
Person of the WeekSelf-introduction: Dorothy Ellis
Hello! I'm Dorothy Ellis. I received my PhD in biostatistics from the University of Florida in August 2023 and joined the Laboratory for Integrative Genomics at RIKEN IMS in October 2023 as a postdoctoral researcher. I was concurrently appointed to iTHEMS in May 2025. My primary research interest is in developing machine learning and data analysis methods (especially unsupervised analysis methods) for multi-omics data.
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2025-05-09
Seminar Report
iTHEMS Theoretical Physics Seminar by Nagare Katayama on May 9, 2025
On May 9, Mr. Nagare Katayama gave a seminar hosted by RIKEN iTHEMS. His talk focused on 2d Cardy-Rabinovici model with the modified Villain lattice formulation. One of the most famous scenarios of the quark confinement problem is the dual superconductor picture. In this picture, the quark confinement is induced by monopole condensation. Still, in the theory with a θ term, we expect that monopole and dyon condensation is induced, as suggested by Cardy and Rabinovici through their intuitive arguments. He discussed that the Witten effect of the theory of two-dimensional compact bosons with the θ term is examined using a modified Villain-type lattice theory that can treat the θ term and dion rigorously. In addition, he constructed the 2d Cardy-Rabinovici model and analyzed the phase diagram through the scaling dimension argument and the anomaly matching constraint. Reported by Okuto Morikawa
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2025-05-08
Paper of the WeekWeek 2, May 2025
Title: ASURA-FDPS-ML: Star-by-star Galaxy Simulations Accelerated by Surrogate Modeling for Supernova Feedback Author: Keiya Hirashima, Kana Moriwaki, Michiko S. Fujii, Yutaka Hirai, Takayuki R. Saitoh, Junnichiro Makino, Ulrich P. Steinwandel, Shirley Ho arXiv: http://arxiv.org/abs/2410.23346v2 Title: Pole-Expansion of Two-Hadron Imaginary-Time Correlation Function -a new method of analysis for unstable states in lattice QCD- Author: Wren Yamada, Osamu Morimatsu, Toru Sato, Koichi Yazaki arXiv: http://arxiv.org/abs/2505.02878v1 Title: Smooth concordance of cables of the figure-eight knot Author: Sungkyung Kang, JungHwan Park, Masaki Taniguchi arXiv: http://arxiv.org/abs/2505.03720v1 Title: Unified exact WKB framework for resonance -- Zel'dovich and complex-scaling regularizations Author: Okuto Morikawa, Shoya Ogawa arXiv: http://arxiv.org/abs/2505.02301v1 Title: Symmetry-adapted sample-based quantum diagonalization: Application to lattice model Author: Kosuke Nogaki, Steffen Backes, Tomonori Shirakawa, Seiji Yunoki, Ryotaro Arita arXiv: http://arxiv.org/abs/2505.00914v1 Title: Shear and bulk viscosity for a pure glue theory using an effective matrix model Author: Manas Debnath, Ritesh Ghosh, Najmul Haque, Yoshimasa Hidaka, Robert D. Pisarski arXiv: http://arxiv.org/abs/2504.20138v1
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2025-05-01
Seminar Report
From Quarks to Neutron Stars: Insights from kHz gravitational waves on April 23, 2025
This conference focused on the role of high-frequency gravitational waves in advancing multi-messenger astrophysics. Key topics included binary neutron star mergers, such as GW170817, and future prospects for observing core-collapse supernovae using electromagnetic signals, neutrinos, and gravitational waves. Discussions highlighted the importance of kilohertz-band gravitational waves in probing the dense interiors of neutron stars, where exotic matter may exist. The seminar also introduced new detector concepts like NEMO in Australia and planned KAGRA upgrades aimed at enhancing high-frequency sensitivity. The event featured expert talks and posters, promoting collaboration and new research directions in nuclear and neutron star physics. Reported by Shuntaro Aoki
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2025-05-01
Paper of the WeekWeek 1, May 2025
Title: High energy extragalactic multimessenger backgrounds from starburst and dead galaxies Author: Ellis R. Owen, Yoshiyuki Inoue, Tatsuki Fujiwara, Albert K. H. Kong arXiv: http://arxiv.org/abs/2504.18721v1 Title: Lindblad dynamics in holography Author: Takanori Ishii, Daichi Takeda arXiv: http://arxiv.org/abs/2504.17320v1 Title: Explosive production of Higgs particles and implications for heavy dark matter Author: Seishi Enomoto, Nagisa Hiroshima, Kohta Murase, Masato Yamanaka arXiv: http://arxiv.org/abs/2504.17127v1 Title: FRG analysis for relativistic BEC in arbitrary spatial dimensions Author: Fumio Terazaki, Kazuya Mameda arXiv: http://arxiv.org/abs/2504.17668v1
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2025-04-24
Paper of the WeekWeek 4, April 2025
Title: Cosmic ray neutrons in magnetized astrophysical structures Author: Ellis R. Owen, Yoshiyuki Inoue, Tatsuki Fujiwara, Qin Han, Kinwah Wu arXiv: http://arxiv.org/abs/2504.15802v1 Title: A magnetar powers the luminous supernova 2023pel, associated with a long gamma-ray burst Author: L. M. Roman Aguilar, M. M. Saez, K. Ertini, M. C. Bersten arXiv: http://arxiv.org/abs/2504.11414v1 Title: Performance guarantees of light-cone variational quantum algorithms for the maximum cut problem Author: Xiaoyang Wang, Yuexin Su, Tongyang Li arXiv: http://arxiv.org/abs/2504.12896v1 Title: Computing $n$-time correlation functions without ancilla qubits Author: Xiaoyang Wang, Long Xiong, Xiaoxia Cai, Xiao Yuan arXiv: http://arxiv.org/abs/2504.12975v1
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2025-04-23
Hot Topic
iTHEMS x academist online event was held on April 19, 2025
iTHEMS held an online lecture event for the general public with the help of Academist Inc., on April 19, 2025. This year’s speakers were Yuuka Kanakubo, Kan Kitamura, Leo Speidel, and Yuki Yokokura, who delivered clear and easy-to-understand lectures that even middle school students could comprehend. Each speaker also served as a commentator for other lectures and facilitated Q&A sessions based on audience questions. During the lunch break, as part of the lunch program, Director Iso, a physicist, and Prof. Fumiharu Kato, a mathematician, engaged in a discussion about the future possibilities of mathematics, moderated by Ms. Shinozaki. The event was organized and hosted by Ms. Michibayashi and Mr. Katada from Academist, who helped make the event a success. The event was attended by 414 people, and at one point there were over 250 in the audience.
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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
102 news in 2025