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RIKEN–IBS Joint Workshop on Mathematical Approaches to Nature Held in Daejeon, Korea, December 9–12, 2025

In December 9–12, 2025, a collaborative workshop jointly organized by the Institute of Basic Science (IBS, Korea) and RIKEN was held in Daejeon, Korea. The workshop aimed to explore the unifying mathematical principles that underlie diverse natural phenomena—from the fundamental interactions that shape the universe to the complex behaviors observed in living systems. From RIKEN, iTHEMS researchers including Derek Inman, Ryo Namba, Alvaro Pastor Gutierrez, Shuntaro Aoki, Sungsik Kong, Amaury Micheli, Puttarak Jai-akson, Ryoko Oishi-Tomiyasu, Che-Yu Chen, and Christy Kelly delivered talks. All the presentations were impressive and thoughtfully prepared so that researchers from different fields could follow and appreciate the content. Indeed, there were many stimulating cross-disciplinary questions, and we enjoyed lively discussions over lunches and dinners, accompanied by excellent (and wonderfully spicy) food. Although the workshop was originally designed to foster collaboration between RIKEN and IBS, connections were already present—for example, through Shuntaro Aoki, a physicist at iTHEMS formerly at IBS, and Shingo Gibo, a mathematical biologist at IBS formerly at iTHEMS. This workshop further strengthened these ties and created new ones. The planning and local organization of the workshop were led by the center of Masahide Yamaguchi (IBS), Yusuke Yamada (IBS), and by Yuto Yamamoto and Ryo Namba at RIKEN iTHEMS, with strong support from IBS and the International Collaboration Section of the Global Strategy Division at RIKEN. We are deeply grateful for their dedicated efforts. I hope that the successful interactions fostered through this workshop will continue to develop even further. (Photos: courtesy of Director Satoshi Iso, RIKEN iTHEMS.) Reported by Gen Kurosawa

2026-01-08
Yuya Kusuki Receives the 22nd (FY 2025) JSPS Prize

Yuya Kusuki (Visiting Scientist, iTHEMS / Associate Professor, Institute for Advanced Study, Kyushu University) has received the 22nd (Fiscal Year 2025) Japan Society for the Promotion of Science (JSPS) Prize. The JSPS Prize was established to recognize outstanding young researchers with exceptional creativity and research ability at an early stage of their careers, and to support their motivation and further development in research. Kusuki has made significant contributions through his research on the development and application of new methods at the interface between quantum gravity and quantum many-body systems. This award recognizes the originality and academic impact of his research achievements. The award ceremony is scheduled to be held on February 3, 2026, at the Japan Academy Hall. Congratulations, Yuya!

2026-01-06
Hokuto Konno receives the 22nd (FY 2025) JSPS Prize

Hokuto Konno (Visiting Scientist, iTHEMS / Associate Professor, the University of Tokyo) received the 22nd (FY 2025) Japan Society for the Promotion of Science (JSPS) Prize on December 16, 2025. The JSPS Prize was established to recognize outstanding young researchers with exceptional creativity and research ability at an early stage of their careers, and to support their motivation and further development in research. Konno was highly commended for his series of research achievements entitled “Family Gauge Theory and Its Applications to Four-Dimensional Topology.” This work elucidates deep connections between gauge theory and low-dimensional topology, and represents an important contribution to the theoretical development of mathematics. The award ceremony is scheduled to be held on February 3, 2026, at the Japan Academy Auditorium. Congratulations, Hokuto!

2025-12-23
Computing n-Time Correlation Functions without Ancilla Qubits

A research team led by Xiaoyang Wang (Postdoctoral Researcher, Quantum Mathematical Science Team, iTHEMS) has proposed a new method for computing n-time correlation functions, which play a central role in understanding the dynamics of quantum many-body systems. The proposed approach requires neither ancilla qubits nor controlled operations, and evaluates correlation functions using only the unitary time evolution of the system of interest. Conventional methods, such as the Hadamard test, rely on ancilla qubits that control the entire system, posing significant challenges for digital quantum processors with limited qubit connectivity and for analog quantum simulators where controlled operations are difficult or impossible to implement. The present work overcomes these limitations and broadens the range of quantum platforms on which multi-time correlation functions can be experimentally accessed. The protocol was demonstrated on IBM quantum hardware with up to 12 qubits, where the team successfully measured the single-particle spectrum of the Schwinger model and the out-of-time-order correlator (OTOC) in the transverse-field Ising model. In addition, an error-mitigation strategy based on signal processing—combining signal filtering and correlation analysis—was introduced, enabling the recovery of ideal noiseless simulation results from noisy experimental data. This work provides a new foundation for experimentally probing complex quantum many-body correlation functions under realistic hardware constraints, thereby strengthening the connection between theoretical predictions and quantum experiments.

2025-12-12
José Said Gutiérrez-Ortega receives the 19th Plant Species Biology Paper Award

José Said Gutiérrez-Ortega (Research Scientist, iTHEMS) has been selected as a recipient of the 19th Plant Species Biology Paper Award. The study analyzes the threats to the biocultural heritage of cycads in the Amami Islands through an international collaboration, including research conducted at RIKEN. The Plant Species Biology Paper Award is presented annually to 1–2 outstanding papers published in Plant Species Biology, selected by vote of the journal’s editorial board. The award was announced on 18 November 2025, and the award ceremony will be held on 20 December 2025 (Sat.) during the meeting of the Society for the Study of Species Biology. Congratulations, José!

2025-12-04
Tomoya Nagai receives the Poster Award at the 29th Interdisciplinary Exchange Evening

Tomoya Nagai (Coordinator, iTHEMS), together with Ayaka Shida (TRIP Promotion Office), Momoko Sato (IMS), and Hiroko Sakuma (Communications Division), has received the Poster Award at the 29th Interdisciplinary Exchange Evening. The Poster Award is presented to several outstanding contributions selected from among 59 poster presentations at this event, which aims to promote communication and collaboration among researchers from diverse fields. Each year, approximately five presentations are selected. The team’s poster investigated researchers’ attitudes and practices regarding the preparation of press releases. Their presentation attracted significant interest from both research and administrative staff within RIKEN. We would like to take this opportunity to express our sincere appreciation to all RIKEN researchers who participated in the survey.

2025-12-04
Seishiro Ono receives the Young Scientist Award of the Physical Society of Japan

Seishiro Ono (Assistant Professor, The University of Tokyo/Visiting Scientist, RIKEN iTHEMS) has received the Young Scientist Award (Division 4) presented by the Physical Society of Japan (JPS). The awarded research is titled “Classification of Topological Superconducting Phases by Symmetry Indicators.” This award recognizes outstanding young researchers under the age of 37 who are expected to contribute to the future of physics. Ono was recognized for his pioneering theoretical work on topological superconductors. Congratulations, Seishiro!

2025-11-13
The 1st Joint General Meeting of RIKEN Quantum and the QII RIKEN User Group on October 24, 2025

On Friday, October 24, the 1st Joint General Meeting of RIKEN Quantum and the QII RIKEN User Group was held at Okochi Hall on the RIKEN Wako campus, bringing together RIKEN researchers who utilize the ibm_kawasaki quantum computer. The meeting featured lively discussions on quantum computing research at RIKEN across a wide range of disciplines, including condensed matter physics, particle, nuclear and astrophysics, biomedical sciences, and the humanities. With over 60 participants, including members from IBM Quantum, the event was a great success. This meeting is expected to further accelerate the development of quantum computing research at RIKEN in the future.

2025-11-12
Miniature satellite NinjaSat discovers an unusually short X-ray burst cycle

An international collaborative research group including Akira Dohi, Special Postdoctoral Researcher, has observed an X-ray binary system known as a “clock burster,” which produces X-ray bursts at regular intervals, using NinjaSat, the CubeSat X-ray satellite led by RIKEN. The team discovered that this object has the shortest burst recurrence time ever recorded, 1.6 hours. For more details, please refer to the related link.

2025-11-06
The tides are changing for white dwarfs

A research team led by Lucy McNeill, a Hakubi Assistant Professor, at the Hakubi Center for Advanced Research, Kyoto University, and a Visiting Scientist at iTHEMS, has revealed that white dwarfs in compact binary systems can become significantly hotter and larger than previously predicted due to strong tidal forces. This “tidal heating” causes white dwarfs to expand to about twice their theoretical size, reaching surface temperatures between 10,000 and 30,000 K. As a result, the onset of mass transfer between the stars may occur at orbital periods up to three times longer than expected. The findings provide new insights into the evolution of white dwarfs and the origins of Type Ia supernovae. For more details, please visit Kyoto University’s press release page via the related link below.

2025-10-22

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RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) is an international research center at RIKEN. It facilitates close collaborations among researchers from different disciplines in theoretical, mathematical and computational sciences. On April 1, 2025, iTHEMS transitioned from a program to a center. The ultimate goal of iTHEMS is to unravel the mystery of the Universe, matter, and life, as well as to solve key problems in modern society through interdisciplinary approaches.

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Director: Satoshi Iso

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Term: January 5 (Mon) - February 4 (Wed) 2026

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