RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences

Ryo Sawada Receives the Young Investigator Award from the Japan Forum of Nuclear Astrophysics (UKAKUREN)

Ryo Sawada, a Special Postdoctoral Researcher at RIKEN iTHEMS, received the 2nd Young Investigator Award from the Japan Forum of Nuclear Astrophysics (UKAKUREN) on March 31, 2026. The research recognized with this award concerns the impact of cosmic-ray environments originating from past supernovae on the formation of Earth-like planets [1]. Congratulations Ryo!

2026-04-09

Akira Dohi Receives the Young Investigator Award from the Japan Forum of Nuclear Astrophysics (UKAKUREN)

Akira Dohi, a Special Postdoctoral Researcher at the RIKEN Pioneering Research Institute (PRI) and concurrently affiliated with RIKEN iTHEMS, received the 2nd Young Investigator Award from the Japan Forum of Nuclear Astrophysics (UKAKUREN) on March 31, 2026. The paper [1], recognized with this award, presents a theoretical study of clocked X-ray bursters. This work also represents the first scientific result from NinjaSat, the world’s first ultra-small general-purpose X-ray satellite, launched on November 11, 2023 under the leadership of the Tamagawa High-Energy Astrophysics Laboratory at RIKEN PRI. For further details, please refer to the press release issued by RIKEN PRI via the related link. Congratulations Akira!

2026-04-09

Observation of Regular Oscillations in Magnetization with a Quantum Computer

A research group including Senior Research Scientist Tomonori Shirakawa demonstrated that discrete time crystals and discrete time quasicrystals can be stably realized for up to 100 time steps on a 133-qubit two-dimensional lattice using IBM’s superconducting quantum computer (here, one time step corresponds to one period of the drive). This result is expected to contribute to experimental validation toward digital quantum simulation of two-dimensional nonequilibrium quantum many-body systems, which are difficult to simulate using classical computation. For further details, please refer to the related link.

2026-04-02

Yuta Sekino received FY2025 RIKEN Research and Technology Incentive Award (RIKEN OHBU Award 理研桜舞賞)

Yuta Sekino (Postdoctoral Researcher, iTHEMS) has been awarded the FY2025 RIKEN Research and Technology Incentive Award (RIKEN OHBU Award). The RIKEN Ohbu Award is presented to early-career researchers and staff members at RIKEN who have demonstrated outstanding achievements in research and development, research support, or contributions to the promotion and dissemination of research outcomes, through active research activities. Sekino was recognized for his proposal entitled “Quantum simulation of spin transport using ultracold atomic gases.” This work presents a novel theoretical framework for simulating and understanding spin transport phenomena in quantum many-body systems using ultracold atom platforms, and is expected to contribute to the advancement of quantum simulation and quantum condensed matter physics. Congratulations, Yuta!

2026-04-01

Farewell message from Takashi Satomi

Our colleague, Takashi Satomi, will be joining Tokyo Denki University as a Lecturer starting April 2026. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Takashi: <i>I would like to share that I will be leaving my position as an SPDR at iTHEMS. Although my term was originally planned to continue, I have decided to end it early as I will start a new position as a lecturer at Tokyo Denki University from April.</i> <i>I have been a member of iTHEMS as an SPDR from April 2024 to March 2026. During this time, I greatly enjoyed the open and interdisciplinary environment. Discussions with researchers from different fields gave me many new ideas and perspectives, and these experiences have been very valuable for my research. I would like to express my sincere thanks to all the members at iTHEMS for their support and kindness.</i> <i>From April, I will continue to be affiliated with iTHEMS as a visiting researcher. I hope to continue discussions and collaborations in the future.</i> <i>Thank you very much for everything.</i>

2026-03-31

Farewell message from Ryosuke Iritani

Our colleague, Ryosuke Iritani, will be joining the Graduate School of Science, The University of Tokyo, as a Project Associate Professor starting April 1, 2026. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Ryosuke: <i>I have spent a rewarding seven years at iTHEMS. My research interests and vision have broadened significantly thanks to the research environment here.</i> <i>Since joining iTHEMS in 2019, I have become increasingly interested in learning and applying mathematics to biological questions. Whenever I encounter new mathematical techniques, I naturally consider how they might be applied to biological systems and how they can bridge our fields. Through this process, I have come to appreciate the truly interdisciplinary nature of science. This shift in my mindset was made possible by the opportunity to interact with such a diverse group of researchers. My goal over the next decade is to conduct biological research that also inspires other communities, such as mathematics and physics. I look forward to seeing where this path leads.</i> <i>The year 2020 was an unprecedented time, not only for iTHEMS but for society as a whole. During that period, we frequently discussed how to maintain an open and productive community, considering various ways to foster engagement within iTHEMS. As we move past the pandemic, I realize that navigating those challenges was an invaluable experience. It served as an important reminder that our research is fundamentally driven by human connection, passion, and well-being, and that we are individuals first and foremost.</i> <i>Finally, I would like to thank all the colleagues, technical staff, assistants, promotion office staff, and directors with whom I have been fortunate to work, discuss, chat, and dine. While I cannot list everyone by name here, I am deeply grateful for every interaction that enriched my time at iTHEMS. Special thanks to Adachi-san and Hamazaki-san for our continued collaboration; to Biology Seminar, Math Seminar, and Information Theory WG members for sharing their time and ideas through our daily interactions; to Catherine, Hatsuda-san, and Iso-san for their encouragement and for fostering such a great environment; and finally, to Wada-san for the continuous support in almost all aspects of my time at iTHEMS.</i>

2026-03-31

Farewell message from Ryo Namba

Our colleague, Ryo Namba, will be joining the Department of Physics, Faculty of Science, Shizuoka University, as a Lecturer starting April 1, 2026. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Ryo: <i>It has been an incredibly stimulating and encouraging five years since I joined iTHEMS in 2021. When I first arrived, restrictions due to COVID-19 limited how often we could come to the office, and I did not have many opportunities to meet other iTHEMS members in person. However, through online meetings and seminars, I sensed a strong and growing enthusiasm for intellectual exchange within the community. Once these constraints were relaxed, people naturally began to gather, and I had many valuable opportunities to interact with colleagues across a wide range of disciplines, including particle and nuclear physics, biology, and mathematics.</i> <i>It was during this time that I was able to expand my research directions significantly. I had the opportunity to participate in study camps with mathematicians and to organize a couple of intensive lecture series spanning physics and mathematics. These experiences have played a central role in shaping my current research focus. iTHEMS offers a truly unique research environment -- not only in its interdisciplinary nature, but also in its openness to member-driven initiatives such as workshops, seminars, and other academic activities.</i> <i>I am deeply grateful for my time at iTHEMS, and I look forward to building on these experiences in my research and educational aspects at Shizuoka University. I sincerely wish for the continued flourishing and development of iTHEMS, and for its current and future members to enjoy their own vibrant and productive time there.</i>

2026-03-31

Farewell message from Sotaro Sugishita

Our colleague, Sotaro Sugishita, will be joining Hokkaido University as an Associate Professor starting April 1st, 2026. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Sotaro: <i>I joined iTHEMS in April 2025 as a research scientist in a cross-appointment position with Kyoto University. Although my time at iTHEMS has been short, I am very grateful for the opportunity to have been part of this unique and inspiring group.</i> <i>Due to my busy work and life in Kyoto, it is a little unfortunate that I did not have many opportunities to visit the Wako campus in person. Nevertheless, every time I visited, I was reminded of what a remarkable place iTHEMS is. There are so many outstanding researchers at iTHEMS, and each visit provided me with new stimulation. The open and interdisciplinary atmosphere of iTHEMS is truly special, and I feel fortunate to have had the experience.</i> <i>I would also like to express my sincere appreciation to the assistants at iTHEMS. Their support was always thoughtful and incredibly supportive, and it helped me greatly throughout. I am deeply grateful not only for the academic environment, but also for the professional and welcoming support system that makes iTHEMS such a pleasant place.</i> <i>I would like to thank everyone at iTHEMS.</i> <i>From April 2026, I will join Hokkaido University as an associate professor. I will also be affiliated with iTHEMS as a visiting researcher. I sincerely look forward to staying in touch and to future interactions and collaborations.</i>

2026-03-31

Farewell message from Yuta Sekino

Our colleague, Yuta Sekino, will be joining the Institute for Advanced Research at Nagoya University as a YLC Assistant Professor starting April 1st, 2026. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Yuta: <i>I have been at RIKEN for seven years. Starting this April, I will join the Institute for Advanced Research at Nagoya University as a YLC Assistant Professor.</i> <i>I first joined the Quantum Hadron Physics Laboratory (Hatsuda Lab.) at the Nishina Center in April 2019 as a JSPS fellow, and from that time I also began attending iTHEMS activities. In October 2021, I moved to the Astrophysical Big Bang Laboratory (Nagataki Lab.) at RIKEN Cluster for Pioneering Research and started a concurrent position in iTHEMS. In July 2024, I officially became a member of iTHEMS as a postdoctoral researcher associated with RIKEN Quantum, and a concurrent member in Hamzaki Hakubi Research Team. During my seven years at RIKEN, I have greatly enjoyed the research environment embracing the iTHEMS spirit of "under one roof."</i> <i>Since I was an undergraduate student, I have been interested in interdisciplinary studies because my main research field, cold atoms, is strongly influenced by other subfields of physics, such as solid-state, nuclear, and particle physics. Therefore, I have greatly enjoyed interactions with researchers not only in physics, but also in mathematics, biology, and data science. I have also appreciated the availability of quantum computing resources.</i> <i>Although I am moving to Nagoya University, I will remain affiliated as a visiting scientist. I would like to continue participating in iTHEMS activities, and I look forward to further interactions with everyone.</i> <i>Finally, I would like to express my sincere appreciation to all the researchers and assistants of iTHEMS for their kind support throughout my time at RIKEN.</i>

2026-03-31

Farewell message from Shigenori Otsuka

Our colleague, Shigenori Otsuka, will be joining the Center for Environmental Remote Sensing, Chiba University, as an Associate Professor starting March 2026. We will all miss him and wish him the best of luck in this new endeavor. Here is a message from Shigenori: <i>I came to RIKEN in January 2013 as a postdoctoral researcher at R-CCS, and I joined iTHEMS as a concurrent member in April 2018. Since then, I have learned a lot from various iTHEMS activities, such as the iTHEMS colloquium series, the lecture series at Nara Women's University, coffee meetings, and collaborations between iTHEMS and Kyoto University. Although my research field, meteorology, has not been a major topic within iTHEMS, I found that we shared many common interests, including fluid dynamics, chaos, data assimilation, and machine learning. After my 13-year career at RIKEN, I moved to Chiba University in March 2026 as an associate professor at the Center for Environmental Remote Sensing. In May 2026, I will return to iTHEMS as a visiting scientist in the Prediction Science Research Team, so please keep in touch. Thank you very much!</i>

2026-03-31

Career Opportunities at RIKEN iTHEMS: Research Administrator and Administrative Support Staff

Interview with Physicist Yuta Sekino [Part Ⅱ]

Interview with Physicist Yuta Sekino [Part Ⅰ]

Interview with Mathematician Takashi Tsuboi [Part Ⅲ]

Next-Generation Researcher Award 2024” Commemorative Interview (3): Keiya Hirashima, RIKEN iTHEMS

Next-Generation Researcher Award 2024” Commemorative Interview (3): Accelerating High-Resolution Galaxy Formation Simulations Using AI Surrogate Models (Takaya Hirashima, RIKEN iTHEMS)

Physicists’ Dialogue: Discussing Quantum Gravity and Black Holes — PART Ⅱ (in Japanese)

Physicists’ Dialogue: Discussing Quantum Gravity and Black Holes — PART Ⅰ (in Japanese)

Interview with Mathematician Taketo Sano [PART Ⅱ] (in Japanese)

Physicists’ Dialogue: Discussing Quantum Gravity and Black Holes — Digest (in Japanese)

Introduction to “Black Hole Recorder” (in Japanese)

Interview with Mathematician Taketo Sano [PART I]

A Century of Quantum Mechanics

Interview with Mathematician Takashi Tsuboi [Part Ⅱ]

Interview with Physicist Yasunori Nomura - Part Ⅳ

Interview with Physicist Yasunori Nomura - Part Ⅲ

Interview with Mathematician Takashi Tsuboi [Part Ⅰ]

Interview with Mathematician Yuto Moriwaki [Part2]

Interview with Mathematician Yuto Moriwaki [Part 1]

Interview with Mathematician Eiji Inoue [Part 2] (in Japanese)

Interview with Physicist Yasunori Nomura - Part Ⅱ

The Connection Between Mathematics and Microbial Research: From Fisheries Science to the Path of Mathematics

Contributed to the 'One Poster per Household' Project – Like the Ones You See in Science Classrooms

Interview with Dr. Misako Tatsuma, a Planetary Formation Theorist

Interview with Mathematician Eiji Inoue [Part 1]

Interview with Physicist Yasunori Nomura - Part I

Interview with Physicist Ryo Namba [Part 2]

Interview with Physicist Ryo Namba [Part 1]

Interview with Ryosuke Iritani, Mathematical Biologist [Part 1]

Theoretical Physicist Tetsuo Hatsuda Interview Vol.2: About Research and Mathematics

Theoretical Physicist Tetsuo Hatsuda Interview Vol.1: About RIKEN iTHEMS

What about climate change in actuality?

The transition to synchronization: from phase reduction to the Kuramoto model

What Are Modular Forms?

Brunn-Minkowski inequality and the Borell-Brascamp-Lieb inequality

Aspects of Quantum Resonance Revisited

Distances and Durations: Cosmology 101

Symmetries of gravity

Birational classification of algebraic varieties

Gelfand duality

Scale transformations in physics and beyond

Machine Learning for Holographic Entanglement Inequalities

Describing Quantum Phenomena with Classical Gravity

Statistical Signatures of Quantum Chaos in Non-Hermitian Systems

Computers as a Playground for Mathematics

The Free Will Theorem in Quantum Mechanics

Renormalization revisited

Renormalization: Awareness of Ignorance

Recipe for soup of quarks and gluons

A subjective view on what is a quantum effect

Mathematical aspects of the entropic uncertainty relation

Forming black holes from stars

Singularity Theorems

Resurgence: making sense out of non-convergent series

How can we use a quantum computer to study the ground state of the hydrogen molecule?

Applications and Extensions of the Nielsen-Ninomiya Theorem in Condensed Matter Physics

COVID-19: then, now, and into the future

Exploring Quantum Spacetime

Classical simulations of quantum computers

When a Cretan says all Cretans are liars

Physical and local observables in gravitational theory

Can you hear the shape of a drum?

Quantum many-body physics with cold atoms

complexity in non-unitary dynamics of photons

Physics Through the Looking Glass

A new B.O.A.T. in astrophysics

Evolution and our daily rhythms

Area law of entanglement entropy in quantum many body systems and its implication in tensor network calculation

Comparison between conventional computers and quantum computers

A glimpse of enumerative geometry

Message-passing algorithms for graphical models

Canonical form of tensor networks in one and two dimensions

The basics of topological band theory

Building something from nothing: a mathematical framework for aperiodic/amorphous sets

Planetary lightning: Current State-of-the-art and outstanding questions

Collective Power of Science ~ from the High-Energy Atmospheric Physics to our New Exploration of the Universe ~

Morse theory and Floer theory

Knot theory and topological semimetals

On Dark Matter

Odd couples of interdisciplinary research

Khovanov homology theory - an introduction to categorification by Dr. Taketo Sano on May 13, 2022

Fundamentals Fest, mini Pre-event on Science "Exploring and Bridging: The Potential of Basic Science"

In Search of Pc pentaquark - Simulate Hadron Interactions with FUGAKU

AAS Journal Author Series: Hirotaka Ito on 2021ApJ…918...59I

Will Useless Knowledge Change the Future? - What is the Black Hole Recorder?

RIKEN 2019 (in Japanese)