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238 news
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2026-10-01
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Farewell message from Osamu Fukushima
Our colleague, Osamu Fukushima, will be joining the Faculty of Science and Engineering, Doshisha University, as an Assistant Professor. We will all miss him and wish him the best of luck in his new endeavor. Here is a message from Osamu: I would like to express my sincere gratitude to everyone at iTHEMS as I leave my position as a Special Postdoctoral Researcher. During my time at iTHEMS, I greatly benefited from its open and interdisciplinary research environment. My research has mainly focused on theoretical and mathematical physics, but interactions with researchers from a wide range of fields encouraged me to broaden my perspective and explore new research directions. I especially appreciated the many stimulating discussions, seminars, and informal conversations at iTHEMS. They often gave me new ideas and perspectives that I would not have encountered within my own field. I would like to thank all the researchers, assistants, and staff for their support and for making iTHEMS such a welcoming place to work. Although I am leaving iTHEMS, I hope to stay connected and continue interacting and collaborating with its members in the future. It has been a great pleasure to be part of the iTHEMS community.
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2026-09-30
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Workshop “Quantum Information: Entanglement of Mathematics & Physics” Held at UBC
From September 21 to 23, 2026, iTHEMS held the workshop “Quantum Information: Entanglement of Mathematics & Physics” at the University of British Columbia (UBC) in Vancouver, Canada. The workshop brought together researchers in mathematics and physics to foster cross-disciplinary discussion through the shared lens of quantum information. Its wide-ranging program covered operator algebras, quantum resource theories, quantum gravity, condensed-matter physics, quantum computing, and quantum error correction. Participants discussed entanglement in these different fields and the mathematical structures underlying quantum information. Approximately 40 researchers from iTHEMS, UBC, and other universities and research institutions in Japan and Canada participated in the workshop. Over the three days, 21 talks were presented. Generous time was also allocated each day for discussion, allowing participants from different fields to share their perspectives and research methods and to engage in lively exchanges. Viewing the participants’ research through the common perspective of quantum information revealed many concrete ways in which insights and methods from distinct fields can complement one another. The broad range of expertise represented by researchers from Japan and Canada gave depth to the discussions and enabled an organic exchange of ideas, with candid questions and challenges addressed across disciplinary boundaries. On the final day, a plenary discussion entitled “Entanglement across mathematics and physics; future iTHEMS–UBC collaboration” explored how the exchanges initiated at the workshop could lead to future research collaboration between iTHEMS and UBC. The workshop also provided a valuable opportunity to build relationships toward sustained academic exchange and a possible Memorandum of Understanding (MOU) between the two institutions. By connecting diverse areas of mathematics and physics through quantum information, the workshop expanded opportunities for new exchanges and collaborative research, while further strengthening the partnership between iTHEMS and UBC.
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2026-09-29
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Mathematical Genomics RIKEN ECL Research Unit Joins OIST Mirror Lab
The Mathematical Genomics RIKEN ECL Research Unit, led by RIKEN ECL Unit Leader Leo Speidel at iTHEMS, has joined an OIST Mirror Lab together with research groups from the Okinawa Institute of Science and Technology (OIST), the Max Planck Institute, and Karolinska Institutet. Mirror Labs are a framework established by OIST to foster long-term research partnerships with institutions in Japan and abroad. Through joint research, researcher exchanges, and the development of early-career researchers, Mirror Labs promote sustained collaboration that brings together the complementary expertise of participating research groups. The newly established “The Evolutionary History of Archaic and Modern Humans Mirror Lab” brings together research groups from OIST, the Max Planck Institute, Karolinska Institutet, and RIKEN to investigate human evolution and population history using genomic data from Neanderthals, Denisovans, and modern humans. The collaboration will explore topics including genetic admixture between archaic and modern humans and the more recent population history of modern humans, particularly in the Japanese Archipelago. The unit will contribute its expertise in population genetic analyses to research on human migration, admixture, and evolution through analyses of modern and ancient genomes.
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2026-09-25
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AI for Science Summer School 2026 Held on August 25–27, 2026
The AI for Science Summer School was held on August 25–27, 2026, at RIKEN Wako Campus, with online participation via Zoom. Jointly organized by the AI as Science Team and the DEEP-IN Working Group, the three-day school brought together more than 40 participants for lectures and hands-on coding sessions exploring how artificial intelligence can support scientific research. The program focused on three practical questions concerning where AI can help address scientific problems, how to choose appropriate methods, and how to apply them effectively. Masato Taki (Rikkyo University/RIKEN) introduced machine learning fundamentals, and Lingxiao Wang (RIKEN/The University of Tokyo) discussed generative modeling. Vinicius Massami Mikuni (Nagoya University) presented foundation models and parameter inference. Naoya Takeishi (The University of Tokyo) covered simulation-based inference. Akinori Tanaka (RIKEN) and Conglong Li (Google DeepMind) explored large language models and their applications to scientific discovery. Hands-on tutorials complemented the lectures. Tutors included Yang-yang Tan (The University of Tokyo), Jinyang Li (KEK/RIKEN), Victor Kawasaki-Borruat (EPFL), and Jingzong Zhang (Fudan University). The sessions covered supervised and unsupervised learning, generative models, data generation, and AI-assisted research workflows. These tutorials connected the lecture material with practical implementation. By combining conceptual introductions with practical exercises, the school offered participants an opportunity to explore how AI methods could be incorporated into their own research. Its emphasis on scientific questions connected the different topics, from interpreting data and generating samples to assisting the research process itself. We thank all lecturers, tutors, participants, and iTHEMS staff for their contributions and support. Reported by Lingxiao Wang
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2026-09-24
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A simulation of the Milky Way galaxy, utilizing exascale supercomputers and AI, advances to Finals for 2026 ACM Gordon Bell Prize
A research group including Dr. Keiya Hirashima of the RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) has been selected as a finalist for the 2026 ACM Gordon Bell Prize for large-scale Milky Way galaxy simulations using exascale supercomputers and AI. Further details will be available soon.
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2026-09-15
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Farewell message from Yuto Yamamoto
Our colleague, Yuto Yamamoto, will be joining the Department of Mathematics, School of Science, Institute of Science Tokyo as an Assistant Professor starting in October 2026. We will all miss him and wish him the best of luck in his new endeavor. Here is a message from Yuto: I am very grateful for the opportunity to have been a member of iTHEMS. During my time here, I enjoyed the stimulating research environment and many opportunities to interact with researchers from different fields. I would like to thank all the members and administrative staff of iTHEMS for their support and for making my time here productive and enjoyable. I have learned a lot from seminars, discussions, and informal conversations with colleagues. Although I am leaving iTHEMS, I hope to stay in touch and to have opportunities to meet and collaborate again in the future. I wish iTHEMS and all its members continued success. Thank you very much for everything.
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2026-09-15
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Farewell message from Kai Murai
Our colleague, Kai Murai, will be joining Tohoku University as an Assistant Professor starting in October 2026. We will all miss him and wish him the best of luck in his new endeavor. Here is a message from Kai: At the end of September, I will leave iTHEMS and move to Tohoku University as an assistant professor. I joined iTHEMS as an SPDR this April. Although my time here was short, it was a very stimulating experience. I especially appreciated the environment where researchers from various fields worked in the same place. It was interesting to be surrounded by research on topics quite different from my own, and I also enjoyed the opportunities to talk with researchers from other fields. I am very grateful to the iTHEMS members who talked with me, as well as to the assistants for all their support. I will come back to iTHEMS for workshops and other occasions, and I look forward to seeing many of you again.
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2026-09-15
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JST-ASPIRE Symposium Held in Palo Alto
On July 24, 2026, the JST-ASPIRE Symposium, “Strengthening Japan–U.S. Research Collaboration through International Talent Circulation,” was held at the Japan Innovation Campus in Palo Alto, California. Organized by the Japan Science and Technology Agency (JST), the symposium brought together representatives of the Japanese government, principal investigators of ASPIRE projects, early-career researchers conducting research in the United States, and U.S.-based researchers. The program focused on research activities supported by ASPIRE, the experiences of early-career researchers working abroad, and future opportunities for Japan–U.S. research collaboration. A panel discussion also addressed how international researcher mobility can contribute to strengthening research capabilities and building sustainable international networks. Four young researchers participating in the RIKEN–Berkeley Mathematical Quantum Science Initiative—Yuuka Kanakubo, Gabriele Di Ubaldo, Haruki Emori, and Shoto Aoki—gave a joint presentation. They introduced their respective research activities and shared experiences gained through conducting research in the United States, as well as their perspectives on future research and career development. Their diverse research areas, ranging from high-energy and nuclear physics to quantum gravity, quantum information, and lattice gauge theory, reflect the broad scope of the RIKEN–Berkeley collaboration. The symposium provided an opportunity to introduce the activities of the RIKEN–Berkeley Mathematical Quantum Science Initiative within the broader ASPIRE program and to consider the importance of sustained researcher exchange between Japan and the United States. Reported by Shuntaro Aoki
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2026-09-08
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Masason Foundation Summer Program Visit to the RIKEN–Berkeley Center on August 11, 2026
Participants in the Masason Foundation’s summer program visited the RIKEN–Berkeley Center at the University of California, Berkeley, on August 11, 2026. The summer program provides young participants with opportunities to broaden their perspectives through visits to universities, research institutions, and other organizations, and through direct interactions with researchers and professionals. The visit began with a tour of the UC Berkeley Physics Department, including an introduction to its history and research environment. This was followed by short presentations by researchers, including Shoto Aoki, Yuka Kanakubo, Gabriele Di Ubaldo, and Akira Dohi, who introduced their research activities to the participants. In the latter part of the program, the participants visited several experimental laboratories at UC Berkeley. Through the presentations, discussions, and laboratory visits, they had an opportunity to learn about a broad range of research activities and to experience firsthand the environment in which cutting-edge research is carried out. The visit provided a valuable opportunity for the young participants to interact directly with researchers at RIKEN and UC Berkeley and to gain a broader perspective on scientific research and possible future career paths. Reported by Shuntaro Aoki
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2026-09-01
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From Vietnam to Korea: A Summer of Quantum Computing
Duc-Truyen Le, a graduate student at Saitama University, is currently affiliated with iTHEMS as an International Program Associate (IPA). This summer, he participated in a series of quantum computing activities in Vietnam and Korea. In Vietnam, his team received an Honorable Mention at an international quantum computing hackathon involving participants from across Southeast Asia. We asked Duc-Truyen to share his experience with the iTHEMS community: From July 9 to 31, I stayed in Vietnam, mainly to prepare for and participate in a major quantum computing event that brought together scientists, industry leaders, policymakers, and government representatives. The event aimed to strengthen collaboration and promote investment in quantum technologies across both the public and private sectors. The program consisted of a series of activities held over more than a week, including workshops, discussions, networking events, and competitions. One of the highlights was the International Hackathon on Quantum Computing for Social Good (QC4SG Vietnam 2026 / 2nd SEA Quantathon), which brought together participants from across Southeast Asia. The competition was highly selective, with more than 500 initial applications. Selected teams went through a training phase before the finalists were invited to Vietnam to present their projects. For more information about the competition, please see the related link below. Among more than 20 finalist teams, comprising around 100 participants, our team, QuanWatt, was honored to receive an Honorable Mention. It was a rewarding experience and a valuable opportunity to exchange ideas with participants from different backgrounds. Our project explored how quantum computing could contribute to the analysis of modern power systems, which are becoming increasingly complex with the growing integration of renewable energy sources and smart-grid technologies. Although considerable work remains before such approaches can be applied in practice, it was encouraging to see increasing interest from both academia and industry in practical applications of quantum computing. Following the program in Vietnam, I traveled to Korea, where I attended a course at the Institute for Basic Science (IBS) from August 1 to 8 on “Quantum Computing for Quantum Field Theory.” This provided another valuable opportunity to learn about the rapidly developing connections between quantum computing and fundamental physics. Overall, these experiences in Vietnam and Korea were both memorable and intellectually stimulating. I am very grateful for the opportunity to participate and for the continued support I have received from iTHEMS.
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2026-08-31
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The 3rd NCTS-iTHEMS Joint Workshop on Theoretical, Mathematical, and Computational Sciences on August 18, 2026
The 3rd NCTS-iTHEMS Joint Workshop on Theoretical, Mathematical, and Computational Sciences was held from August 18 to 21, 2026, at the NCTS Physics Lecture Hall in the Cosmology Hall of National Taiwan University (NTU), Taipei. This was the third workshop in the series jointly organized by Taiwan's National Center for Theoretical Sciences (NCTS) and RIKEN iTHEMS, following the first workshop hosted by NCTS in 2024 and the second hosted by RIKEN in 2025. This year's workshop carried special significance as the first major joint activity after the signing ceremony held at NTU on April 23, 2026, where iTHEMS and NCTS launched the joint research initiative "Mathematical Frontiers for Matter, Life, and the Universe." The initiative, signed by iTHEMS Director Satoshi Iso and NCTS Directors Pei-Ming Ho and Ming-Lun Hsieh, aims to foster outstanding early-career researchers and to promote researcher exchanges, international symposia, and collaborative research between the two institutions. Reflecting this spirit, the scope of the workshop expanded beyond previous editions to encompass theoretical physics, mathematics, and computational sciences. The four-day program featured 28 talks and 10 posters. Three plenary lectures were delivered by Tzu-Chieh Wei (Stony Brook University) on the stability of quantum many-body phases against time-dependent perturbations, Etera Livine (ENS Lyon) on spinfoam approaches to quantum gravity, and Tan Bui-Thanh (UT Austin) on model-constrained scientific machine learning for digital twins. Thirteen invited speakers from RIKEN iTHEMS and twelve from Taiwanese universities and Academia Sinica presented research spanning high-energy physics, gravity, condensed matter physics, quantum information and computing, geometry and topology, applied mathematics, machine learning, and scientific AI. In the poster session, ten presenters, mostly students and early-career researchers, introduced their work in three-minute flash talks followed by lively discussions over coffee. The directors of both institutions delivered the opening and closing remarks, and the iTHEMS and NCTS organizers held internal discussions on future joint activities during the workshop. The interdisciplinary atmosphere led to many cross-field conversations during the coffee breaks, the poster session, and the banquet, and several new contacts between researchers of the two institutions were established. We thank the NCTS staff for their excellent local organization and all speakers and participants for making the workshop a success. We look forward to continuing the series and to deepening the collaboration between NCTS and iTHEMS under the new initiative. Reported by Ching-Kai Chiu
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2026-08-17
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Farewell message from Sungsik Kong
Our colleague, Sungsik Kong, will be joining Sejong University in South Korea as a tenure-track Assistant Professor in September 2026. We will all miss him and wish him every success in this exciting new chapter. Here is a message from Sungsik: I joined iTHEMS in August 2025, and over the past year I have had the privilege of working in an exceptional research environment. Starting in September 2026, I will be joining Sejong University in South Korea as a tenure-track Assistant Professor. While I am excited about this move, I am also sad to be leaving my position as a Research Scientist at iTHEMS. My time at RIKEN has been both challenging and incredibly rewarding. I am deeply grateful to RIKEN and iTHEMS for giving me the opportunity to pursue the scientific questions I am passionate about. I will miss iTHEMS' collaborative atmosphere. I have had the chance to learn from researchers across many different fields, many that I would never have had the opportunity to explore otherwise. Those seminars, colloquiums, and conversations have broadened my perspective, sparked new ideas, and made my time here truly valuable and memorable. If you ever visit Seoul, please don't hesitate to get in touch. Thank you all so much. It has been a real pleasure.
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2026-07-29
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2026 iTHEMS Visit by the National Sun Yat-sen University, Taiwan
On June 25, a group of 3 professors and 13 students from National Sun Yat-sen University, Taiwan, visited RIKEN . The purpose of the visit was to immerse the students in RIKEN’s multidisciplinary research environment and introduce them to stateoftheart scientific methodologies. It also aimed to inspire their future research careers while exploring opportunities for academic exchange and longterm collaboration between both institutions. First, the group visited RIKEN Nishina Center for Accelerator-Based Science, hosted by Dr Claudio Santonastaso & Dr Seiya Sakai. Next visit was RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), hosted by Dr. Gen Kurosawa. Last visit was RIKEN Center for Quantum Computing, hosted by Dr. Franco Nori. Gen Kurosawa, Senior Research Scientist, introduced iTHEMS’s interdisciplinary research environment and explained how mathematical methods from physics can be applied to important questions in biological clocks, leading to testable predictions that are verified experimentally.
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2026-07-24
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Farewell message from Puttarak Jai-akson
Our colleague, Puttarak Jai-akson, will be joining the Graduate School of Science, Kyoto University, as a Program-Specific Researcher, starting in August 2026. We will all miss him and wish him every success in this exciting new chapter. Here is a message from Puttarak: I would like to share that I will be leaving my position as a Postdoctoral Researcher at iTHEMS. I joined iTHEMS in November 2022, and after nearly four wonderful years, I will be moving to a new position as a Researcher at Kyoto University, starting in August 2026. During my time at iTHEMS, I greatly enjoyed the open, friendly, and interdisciplinary research environment. The opportunity to interact with researchers from diverse fields has broadened my perspective, inspired many new ideas, and significantly enriched my research. I am deeply grateful to all the members of iTHEMS for their support, encouragement, and the many enjoyable discussions we have shared. I would also like to express my heartfelt thanks to our wonderful iTHEMS Assistants, whose kindness, professionalism, and constant support made my time at iTHEMS all the more enjoyable. Although I am leaving my full-time position, I am pleased to continue my affiliation with iTHEMS as a Visiting Scientist. I sincerely hope to continue our discussions and collaborations in the future. If you happen to visit Kyoto University, please don't hesitate to let me know. I would be very happy to catch up and continue our conversations. Thank you all very much for everything. It has been a privilege to be part of iTHEMS, and I wish everyone continued success.
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2026-07-16
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2026 iTHEMS Visit by the University of California San Diego Global Seminar Program
On July 8, Dr. Stanley Lo, Teaching Professor in the Department of Cell and Developmental Biology at the School of Biological Sciences, UCSD, visited iTHEMS together with 24 undergraduate students. The purpose of the visit was to learn about iTHEMS and its research activities while supporting the students’ learning about human diversity and the relationship between science and society. Thomas Hitchcock, Research Scientist at iTHEMS, hosted the lecture. He introduced his academic and professional background and presented his current research on evolution, ecology, and genetics.
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2026-06-11
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The First RIKEN Quantum International Workshop on Frontiers of Quantum Computing Applications and Quantum-HPC Integration on May 25-26, 2026
The First RIKEN Quantum International Workshop on Frontiers of Quantum Computing Applications and Quantum–HPC Integration was held from May 25 to 26 at the Large Conference Room on the 2nd floor of the Administrative Headquarters, RIKEN Wako Campus. The workshop featured an entirely invited program, consisting of 13 plenary presentations (40 minutes each) and 9 highlight presentations (20 minutes each). The presentations covered a broad range of fields—including quantum chemistry, life sciences, condensed matter physics, atomic physics, and high-energy physics—with a primary focus on the theme of quantum–HPC hybrid integration. With more than 130 registered participants, each presentation was followed by lively and engaging discussions. Furthermore, the networking reception held on the evening of the first day was well-attended, fostering active interaction and collaboration among researchers from universities, national research institutes, and private industries. This workshop is expected to drive further advancements in quantum computing through quantum–HPC hybrid integration. Reported by Shinichiro Fujii
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2026-05-18
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Mayor Takeshi Sakamoto of Itabashi City Visits iTHEMS on May 14
On May 14, Takeshi Sakamoto, Mayor of Itabashi City, visited iTHEMS and met with Center Director Satoshi Iso. Mayor Sakamoto introduced Itabashi City’s initiatives and basic development plan, followed by Director Iso’s presentation on the vision and activities of iTHEMS. The mayor then toured the iTHEMS spaces on the 2nd to 4th floors of the east side of the Main Research Building, where he interacted with researchers engaged in active discussions. In addition, at the Memorial Archives Room, Mayor Sakamoto viewed valuable historical materials that are also connected to Itabashi City.
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2026-05-18
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Talk Event “Useless Science and Art vol.2” Held at the Museum of Contemporary Art Tokyo
As a related event to the exhibition MOT Collection: Mission∞Infinity – Space × Art × Quantum, currently being held at the Museum of Contemporary Art Tokyo, the talk event “Useless Science and Art vol.2: Prototyping ‘Useless’ Science and Art” took place on Wednesday, May 6, 2026. This event was organized in connection with Black Hole Recorder, a work inspired by quantum black hole theory. Researchers and creators gathered to discuss the new possibilities that can emerge from ideas that may initially appear “useless.” Approximately 110 people attended the event. During the talks, the speakers introduced the conceptual framework of Black Hole Recorder and the theoretical ideas behind its creation. Visitors were also able to experience part of the work through a listening session held at the venue. The speakers included Tetsuo Hatsuda (Team Director, Quantum Mathematical Science Team, RIKEN iTHEMS), Koji Hashimoto (Professor, Graduate School of Science, Kyoto University), Yoshihiro Kozuka (Creative Director, ADK Marketing Solutions), and Haruka Kodama (Experience Designer, ADK Marketing Solutions). From their respective professional perspectives, they exchanged ideas on collaborations between science and art. Professor Hashimoto also discussed his cross-disciplinary activities exploring the theme of “Quantum × Music,” including translating concepts from quantum physics into musical expression. This program was held as the second installment of an ongoing talk series. Following the first session, the discussion further explored the significance of initiatives that bridge academic research and creative practice. After the main event, a wrap-up talk featuring participating artists, creators, and researchers from the exhibition was also held, with the same members continuing the discussion.
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2026-05-14
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iTHEMS x academist Online Event "World of Mathematical Sciences 2026" on April 18, 2026
RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) held the online event “Exploring the World of Science through Mathematics 2026” on Saturday, April 18, 2026, in collaboration with academist Inc. The event featured a series of lectures spanning a wide range of scientific fields, all connected through the perspective of mathematical sciences. Junnosuke Koizumi, Osamu Fukushima, Muzi Hong, and Kenji Okubo each gave presentations in their respective areas of expertise. The talks incorporated concrete examples to facilitate understanding, and also included discussions with commentators as well as Q&A sessions with participants. In addition, during the lunch break, Honorary Research Scientist Shun-ichi Amari and iTHEMS Director Satoshi Iso led a special session titled “Intelligence and Learning in the Age of AI.” Through an interactive dialogue with practical examples, they discussed how AI is influencing human intellectual activity and transforming approaches to learning. According to the post-event survey, overall satisfaction with the event was high. While some participants commented that the presentations were “somewhat difficult,” many also described them as “easy to understand.” A total of 303 participants (528 cumulative attendees) joined the event, with the maximum number of simultaneous connections reaching 184.
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2026-05-11
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Mathematical Genomics ECL Research Unit Retreat, 27–28 April 2026
On 27 - 28 April, the Mathematical Genomics ECL Research Unit went on a two-day retreat to SUURI-COOL Kyoto. With two new members joining in April, the retreat was a great chance for everyone to get together outside our usual work environment. Our unit started in late 2024 and over the past year and a half, we have grown to six members: Leo Speidel, Unit Leader, Lucas Sort and Aina Colomer i Vilaplana, both postdocs who joined last year, Tomoko Iwanami who is our most valued assistant, and most recently, we welcomed two additional members to our unit, postdoctoral scientist Alba Nieto Heredia and PhD student Satsuki Hirasawa. As a team, our expertise lies in modelling how our genomes are inherited through generations and using statistical inference to uncover the stories hidden within them. Our DNA can tell detailed stories about human history and prehistory, including migration, adaptation, and the origins of modern humans, while also uncovering the biological processes that shape evolution and influence human health today. We decipher these from the genomes of many thousands of present-day people, as well as from DNA sequenced from ancient human bone. The signatures left in our DNA are often subtle but preserve the stories of ordinary people not necessarily recorded in history books. At the retreat, we explored topics beyond our usual day-to-day activities. We organised three sessions: first, a mock Kakenhi grant exercise where each of us pitched a potential research idea; second, a series of practical tutorials on techniques we use in our day-to-day work, including figure design (Aina), AI tools in VS Code (Alba), LaTeX (Lucas), ancient DNA sequencing (Satsuki), and the many quirks of administration (Tomoko); and finally, a deep dive into Japanese history, spanning from prehistoric Japan, the rise of early states, through the world of Heian-period court culture, and all the way up to the Edo period. Attached is a photo of us at Byodo-in Temple in Uji, Kyoto, one of the oldest surviving temple complexes of the Heian period in Japan, already celebrated in classical literature written more than 1,000 years ago.
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2026-05-11
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RIKEN iTHEMS and Taiwan’s NCTS Launch Joint Research Initiative to Foster Outstanding Early-Career Researchers, Hold Signing Ceremony
In April 2026, the RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) and the National Center for Theoretical Sciences (NCTS) in Taiwan launched a joint research initiative titled “Mathematical Frontiers for Matter, Life, and the Universe,” which aims to address fundamental questions in matter, life, the universe, and society through interdisciplinary approaches centered on mathematics. A signing ceremony was held on April 23 at National Taiwan University (NTU). Representing RIKEN at the ceremony were Satoshi Iso (Director, iTHEMS), Shigehiro Nagataki (Deputy Director, iTHEMS; Division Director, Division of Global Collaborations and Research Talent Development), Yasuyuki Kawahigashi (Deputy Director, iTHEMS), and Tomoya Nagai (Coordinator, iTHEMS). Participants from National Taiwan University (NTU) included Chih-Hsing Yang (Executive Vice President, NTU), Chung-Chih Wu (Vice President for Research and Development (R&D), NTU), Pei-Ming Ho (Director, NCTS), and Ming-Lun Hsieh (Director, NCTS), along with theoretical researchers in physics, mathematics, and related scientific fields from multiple institutions. Through this collaboration, the two institutions aim to further strengthen their partnership by expanding researcher exchanges, co-organizing international symposia, and promoting international collaborative research in cutting-edge theoretical sciences. In addition, this partnership seeks to provide early-career theoretical researchers with an environment that offers a high degree of academic freedom, while creating valuable opportunities to collaborate with researchers across a broad range of disciplines and interdisciplinary fields within Asia’s leading theoretical physics and mathematics communities.
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2026-04-30
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Farewell message from Iao-Fai Io
Our colleague, Iao-Fai Io, will be returning to National Taiwan University starting in May to complete his Ph.D. We will miss him and wish him all the best in his future career. Here is a message from Iao-Fai: I joined iTHEMS in May 2025 as an International Program Associate (IPA). Over the past year, I have been very happy to be part of the iTHEMS member. RIKEN is one of national research institute in Japan, during my time here I had the opportunity to attend many high-quality seminars and workshops. I have also had the opportunity to visit and interact with member from different centers in RIKEN(such as CEMS, FQSP, RQC, etc.). I am also very grateful for the “coffee meetings” and “iTHEMS Now & Next” events, which helped me understand iTHEMS and learn about research which is beyond my own field. I would like to express my sincere gratitude to my host researcher, Dr. Ching-Kai Chiu. He has taught me a great deal about research, particularly in superconductivity and altermagnetism, which has significantly improved my research abilities in condensed matter theory. Whenever I encountered difficulties in my research, he was always willing to discuss them with me and suggest valuable advice. I am also grateful to him for introducing me his collaborators, including Congcong Le (a former iTHEMS member) and collaborators from China. In addition, I would like to thank him for his support during my visits abroad. I would also like to thank Tomoko Iwanami-san and Chikako Ota-san for their administrative support. In addition, I am grateful to all the people I have met at iTHEMS over the past year (such as Yan, Xiaoyang, Duc-Truyen, Tianyin, Zhe, Jinyang, Rumi, Yuta, Brian, Shuntaro, Lingxiao, Muzi, Sho, Satsuki, Iso, Haruki, Tada, Hatsuda, etc.). Over the coming year, I will return to National Taiwan University to complete my Ph.D., while also beginning to apply for postdoctoral positions. In the future, if I have the opportunity, I would be happy to visit RIKEN iTHEMS again. I sincerely hope to see you all again in the near future.
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2026-04-23
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The third RIKEN Quantum internal meeting on March 30, 2026
On Monday, March 30, the third RIKEN Quantum internal meeting was held in the Large Conference Room (2F, Administrative Headquarters) at RIKEN, Wako, attended by a total of over 50 RIKEN Quantum members and related researchers. At this meeting, Yahui Chai and Danny Jammooa, who were invited from overseas, gave presentations on their recent research, 'Quantum Simulation of Particle Scattering' and 'Parametric Matrix Models,' respectively. Furthermore, Jian Xu, who recently joined RIKEN Quantum, presented the research he plans to pursue at the institute. In addition, 12 researchers from various fields associated with RIKEN Quantum, who also serve as RIKEN TRIP visiting scientists for collaborative projects, gave short talks to introduce their work. At the banquet following the meeting, members, including those meeting for the first time, exchanged ideas in a relaxed atmosphere, leading to fruitful discussions for the further development of RIKEN Quantum. Reported by Shinichiro Fujii
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2026-04-10
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Talk Event “Useless Science & Art” Held at the Museum of Contemporary Art Tokyo
As a related program of the Mission∞Infinity exhibition at the Museum of Contemporary Art Tokyo, the talk event “Useless Science & Art: The Usefulness of ‘Useless’ Science and Art” was held on Saturday, March 21, 2026, attracting 119 participants. This event was organized as a continuation of “Entangle Moment [Quantum, Sea, and Universe] × Art,” held at the EXPO Messe “WASSE” during Expo 2025 Osaka, Kansai, from August 14 to 20, 2025, which welcomed approximately 60,000 visitors in total. Continuing the momentum of that initiative, the event brought together iTHEMS researchers and artists to discuss the value of scientific research and artistic expression that may initially appear “useless.” Using Black Hole Recorder, a work inspired by quantum black hole theory, as a starting point, participants shared multifaceted perspectives on the relationship between science and creativity. Audience members also actively engaged in the discussion, raising numerous questions and exchanging ideas about the relationship between science and art and how their value should be understood. The venue was filled with lively and enthusiastic discussion throughout the event. Expanding further on the fusion of science and art sparked by the Expo, the event provided a valuable opportunity to reflect on the nature of knowledge from a long-term perspective. The Mission∞Infinity: Space, Quantum, and Art exhibition at the Museum of Contemporary Art Tokyo, including the display of Useless Prototyping Studio’s Black Hole Recorder, will continue through Wednesday, May 6, 2026 (national holiday).
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2026-04-02
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KEK-iTHEMS Workshop “Concepts of Quantum and Spacetime” on March 9, 2026
We held the workshop “Concepts of Quantum and Spacetime” (at KEK in Japan from 9 to 12 March 2026), a joint workshop organized by KEK Theory Center and RIKEN iTHEMS. The two fundamental questions, “What is quantum?” and “What is spacetime?”, are deeply intertwined. The workshop discussed the question “How can quantum theory and spacetime be understood in a consistent manner?” from a fundamental and broad perspective and shared various ideas with open minds, to find directions guiding quantum theory over the next 100 years. The topics were diverse: foundations of quantum theory, quantum gravity, emergence of spacetime, formulation of semi-classical gravity, experimental aspects of fundamental properties in nature, and foundations of quantum many-body systems and thermodynamics. Around 90 researchers from various countries, generations, and fields came together. (Around 40% of these were from overseas.) The 14 keynote speakers—many of whom are rarely seen in Japan—shared their visions on quantum theory and spacetime. (The talk slides are available in the website.) The 13 selected short talks and the 22 poster presentations were of a high standard, leading to lively discussions; we also held a poster award competition. Interestingly, the disagreements and confusion arising from differences in their expertise and viewpoints actually gave rise to new discussions and ideas. This was likely due to the open atmosphere of sincere engagement that emerged because the thema was not confined to specific methods or theoretical frameworks. Furthermore, small yet significant touches—such as providing boxed lunches to keep the lively atmosphere of the lecture hall going during the lunch break, and setting up whiteboards in open spaces to encourage discussion—proved effective. These efforts fostered constant, natural interaction and lively discussion throughout the venue. Participants did not merely listen; they truly shaped the workshop. (Visit the website to see photos during the event.) Many participants commented that it was an interesting and wonderful workshop. We also received feedback such as, “I gained ideas for future research,” and “This provided valuable insights for organizing future workshops.” These are the result of the deep curiosity shared by all participants regarding fundamental questions, “What is quantum?” and “What is spacetime?” It is precisely such curiosity that will naturally give rise to new ideas and collaborative research and connect the world. I hope that workshops embodying a similar spirit will be held around the world on a variety of themes in the future. Reported by Yuki Yokokura, chair of organizing committee.
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2026-03-31
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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 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 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. From April, I will continue to be affiliated with iTHEMS as a visiting researcher. I hope to continue discussions and collaborations in the future. Thank you very much for everything.
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2026-03-31
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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 have spent a rewarding seven years at iTHEMS. My research interests and vision have broadened significantly thanks to the research environment here. 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. 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. 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.
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2026-03-31
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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: 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. 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 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.
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2026-03-31
Hot TopicFarewell 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 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. 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 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 would like to thank everyone at iTHEMS. 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.
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2026-03-31
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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 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 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." 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. 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. 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.
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2026-03-31
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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 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!
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2026-03-24
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Farewell message from Kan Kitamura
Our colleague, Kan Kitamura, will be joining the Department of Mathematics, College of Science, Rikkyo University as an Assistant 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 Kan Kitamura: I joined iTHEMS as a special postdoctoral researcher (SPDR) in April, 2024. It has been a great pleasure to spend these two years in such a wonderful research environment. This department is built on a unique concept where researchers from diverse fields of theoretical science work together under one roof. Being able to casually interact with colleagues from different areas has continually stimulated my intellectual curiosity and provided me with a lot of inspiration. In 2025, iTHEMS transitioned into a center, and I feel fortunate to have been there at that time. The evolving environment kept my research experience fresh and exciting. I feel that my research has progressed well during my time here, and I have no doubt that the creative atmosphere of iTHEMS played a significant role in this. I would like to express my deep gratitude to my colleagues for the discussions, both formal and informal, and to the staff for their support. Although I will be leaving my current position, I will remain affiliated as a visiting scientist, and I hope to continue interacting with all of you. I wish iTHEMS every success and continued growth.
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2026-03-11
Hot Topic
RIKEN–Berkeley Workshop on Quantum Gravity 2025 on October 23-24, 2025
The RIKEN–Berkeley Workshop on Quantum Gravity 2025 was held on October 23–24, 2025, at the RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), RIKEN Wako Campus, Japan. The workshop marked the first meeting of a new collaboration between the Leinweber Institute for Theoretical Physics (LITP) at the University of California, Berkeley and iTHEMS. A total of 38 participants attended the workshop. The workshop brought together researchers working on quantum gravity and related areas to discuss recent developments and future directions in the field. The scientific program featured talks on a range of topics, including quantum aspects of spacetime, black hole physics, holography, and their connections to quantum information and condensed matter physics. The meeting provided an opportunity for researchers from Berkeley, RIKEN, and other institutions to exchange ideas and explore potential collaborations. Discussions during the workshop highlighted current progress in the field and encouraged interactions among participants from different research backgrounds. The workshop served as the first step in strengthening collaboration between LITP and iTHEMS, with the aim of promoting continued exchanges and future joint research activities between the two institutions. The workshop was organized by Gabriele Di Ubaldo (LITP Berkeley and RIKEN iTHEMS), Tetsuo Hatsuda (RIKEN iTHEMS), Masazumi Honda (RIKEN iTHEMS), Satoshi Iso (RIKEN iTHEMS), Masamichi Miyaji (RIKEN iTHEMS), Shigehiro Nagataki (RIKEN iTHEMS) and Yasunori Nomura (LITP Berkeley and RIKEN iTHEMS). Reported by Masamichi Miyaji
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2026-03-11
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XIIIth International Symposium on Nuclear Symmetry Energy (NuSym25) on September 8-13, 2025
The XIIIth International Symposium on Nuclear Symmetry Energy (NuSym25) was held from September 8 to 13, 2025, at the Integrated Innovation Building, RIKEN Kobe Campus. The symposium brought together approximately 78 researchers working on nuclear physics, astrophysics, and related fields to discuss recent developments in the study of the nuclear equation of state (EoS) and nuclear symmetry energy. The nuclear symmetry energy plays an important role in understanding properties of neutron-rich nuclear matter, which is relevant for nuclear structure, heavy-ion collisions, and astrophysical phenomena such as neutron stars and their mergers. The symposium aimed to connect experimental, observational, and theoretical efforts across these areas. The scientific program included invited and contributed talks covering a broad range of topics, including nuclear structure and reactions, heavy-ion collision experiments and transport model simulations, microscopic calculations of dense neutron-rich matter, and astrophysical observations of compact stars. Recent progress in multi-messenger observations of neutron stars and their implications for the nuclear equation of state were also discussed. The symposium provided an opportunity for researchers from different communities to exchange ideas and strengthen collaborations in addressing common challenges related to the nuclear equation of state. Following the main scientific sessions, a meeting of the Transport Model Evaluation Project (TMEP) was held to discuss benchmarking and uncertainty quantification in transport model simulations for heavy-ion collisions. Reported by Shuntaro Aoki
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2026-03-09
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RIKEN–Nara Women’s University Joint Diversity Promotion Workshop 2026 was held
Students from various courses at Nara Women’s University—including mathematics, physics, chemistry, biological sciences, and environmental sciences—visited RIKEN for two days, March 2–3. A total of 21 students (first-, second-, and third-year undergraduate students and first-year master’s students) participated in the visit. During their stay, the students toured several research facilities at RIKEN, including the Multiscale Brain Function Research Team at the RIKEN Center for Brain Science (CBS), the RIBF facility at the RIKEN Nishina Center, and the Optical Quantum Control Research Team at the RIKEN Center for Quantum Computing (RQC). At iTHEMS, they attended talks by Megumi Oya (Postdoctoral Researcher, Medical Science Data-driven Mathematics Team, iTHEMS) and Leo Speidel (iTHEMS ECL Research Unit Leader). At each laboratory, the students had the opportunity to observe cutting-edge research up close near experimental equipment and learn about ongoing research activities. During the evening networking session with RIKEN researchers, they asked questions to iTHEMS researchers and learned about researchers’ daily lives and career paths. The event provided a valuable opportunity for meaningful交流 and discussion for the students. This diversity promotion initiative is conducted jointly by the Faculty of Science at Nara Women’s University and RIKEN iTHEMS, and is organized in conjunction with a series of lectures held at Nara Women’s University.
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2026-03-04
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RIKEN President Makoto Gonokami Visits the RIKEN Berkeley Center
On February 26, 2026, Makoto Gonokami, President of RIKEN, visited the RIKEN Berkeley Center (Photo left). During his visit, the Center’s mission and organizational concept were introduced, followed by a tour of the office facilities. President Gonokami then met with the RIKEN Berkeley Fellows currently conducting research in UC Berkeley (UCB) and Lawrence Berkeley National Laboratory (LBNL) (Photo right). The fellows presented overviews of their research projects and shared their experiences regarding the academic and living environment in Berkeley. They highlighted the stimulating research atmosphere and discussed their perspectives for further development. Before and after the Center visit, President Gonokami also exchanged views with Steve Kahn (UCB, Dean of Mathematical and Physical Sciences), Yasunori Nomura（UCB, Director of the Leinweber Institute for Theoretical Physics）, and Hitoshi Murayama (UCB, Professor, Physics Department), and toured quantum computing facilities at Berkeley. This visit is expected to further strengthen collaboration and researcher exchange between RIKEN and Berkeley. The RIKEN Berkeley Center will continue to promote academic partnership and serve as a hub for international research collaboration. Photo left: In front of the RIKEN Berkeley Center signboard. From left to right: Center Director Iso, RIKEN President Makoto Gonokami, Wick Haxton, RIKEN Berkeley Center Director Nagataki, and Domain Director Hatsuda. Photo right: President Gonokami in discussion with RIKEN Berkeley Fellows. From left to right: Gabriele Di Ubaldo, Jan Shuette-Engel, Yuka Kanakubo, Domain Director Hatsuda, and Center
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2026-02-03
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“Black Hole Recorder” Exhibited in “Mission ∞ Infinity | Space + Quantum + Art”
ADK Marketing Solutions Inc. is exhibiting the interactive science-art installation “Black Hole Recorder”, created in collaboration with iTHEMS, as part of the special exhibition “Mission ∞ Infinity | Space + Quantum + Art”, currently being held at the Museum of Contemporary Art Tokyo from January 31 to May 6, 2026. This work is a prototype model of a future information storage device inspired by quantum black hole theory. Using the black hole as a metaphor for an object capable of containing enormous amounts of data, the installation invites visitors to record human voices and sounds, imagining them being delivered into the distant future or even into space. Through artworks that merge space science, quantum theory, and artistic expression, the exhibition offers a unique opportunity to experience the invisible world and explore new possibilities for the future. For more information, please see the related links.
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2026-01-15
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iTHEMS Colloquium by Hiroki R. Ueda on October 10, 2025
On October 10, 2025, Dr. Hiroki Ueda, Professor at the University of Tokyo’s Graduate School of Medicine and former Team Leader at RIKEN Center for Biosystems Dynamics Research (BDR), delivered a splendid iTHEMS Colloquium talk on the Wako campus. His lecture, titled “Why Do We Sleep? The Role of Calcium and Phosphorylation in Sleep,” attracted a wide audience—not only researchers from iTHEMS but also colleagues from other RIKEN centers, including the Pioneering Research Institute (PRI) and the Center for Brain Science (CBS), as well as administrative staff. The talk was highly engaging and accessible to specialists and non-specialists alike. Dr. Ueda began with an overview of the long history of sleep research and the major unsolved questions that continue to inspire the field. He then presented his group’s recent discoveries on the role of calcium in sleep regulation. He also introduced a new theoretical framework—the WISE (Wake Inhibition Sleep Enhancement) mechanism—together with its mathematical modeling. Because sleep is closely connected to our daily lives, the audience had many questions from diverse perspectives, and Dr. Ueda kindly addressed each of them in detail. During and after the colloquium, including at the dinner that followed, we had stimulating discussions with him about his group’s model and potential new directions for sleep research and related areas of life science. We are deeply grateful to Dr. Ueda for his inspiring lecture and for sharing his broad expertise with our community. (Photos: courtesy of Assistant Chikako Ota, RIKEN iTHEMS.) Reported by Gen Kurosawa
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2026-01-08
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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
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2025-12-12
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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.
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2025-12-01
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Mathematical Sciences Outreach Workshop 2025 on November 14, 2025
From November 14 to 16, 2025, the Workshop Outreach of Data Descriptive Science was held at the Institute of Mathematics for Industry (IMI), Kyushu University, as well as online. The workshop was supported by the MEXT Grant-in-Aid for Scientific Research (KAKENHI), Transformative Research Areas (A) 2022–2026 “Establishing data descriptive science and its cross-disciplinary applications”. Building on the Journalist-in-Residence (JIR) program, this workshop aimed to explore new forms of science communication through dialogue between researchers and journalists. Approximately 40 participants—including researchers, science journalists, editors, and public relations professionals—attended both in person and online. Over the course of three days, the program featured research presentations on topics such as data descriptive science, optimal transport theory, and statistics, alongside reports from the fields of publishing, journalism, and science communication. These sessions fostered active discussions on how to effectively convey research outcomes to society. By bringing researchers and journalists together in a shared forum, this workshop provided an important opportunity to bridge mathematical sciences and society. It highlighted diverse perspectives on the societal sharing of specialized knowledge and is expected to contribute to the future development of outreach activities and science communication. Photo by Hiroaki Kono
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2025-11-12
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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.
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2025-11-06
Hot Topic
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.
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2025-10-22
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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.
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2025-10-20
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Paper Accepted at NeurIPS 2025, One of the World’s Premier Conferences in AI
A paper by Tsubasa Masumura and Associate Professor Masato Taki (Visiting Scientist at iTHEMS), both from Rikkyo University, has been accepted for presentation at NeurIPS 2025, an international conference in the field of machine learning. In this study, the authors proposed a new Transformer architecture that incorporates the principles of associative memory, successfully mitigating the issue known as “rank collapse” both theoretically and experimentally. The proposed method improves model performance without introducing additional parameters, offering potential contributions to the further advancement of large language models and generative AI. NeurIPS 2025 will be held in December 2025 in San Diego, USA. For more details, please refer to the Rikkyo University press release via the related link below.
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2025-10-16
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Students from OTEMAE Senior High School Visited iTHEMS through the “Math Tour” Program
On October 2–3, 2025, students from OTEMAE Senior High School in Osaka visited the RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) as part of the “Math Tour” training program. During their visit, the students attended lectures given by iTHEMS researchers and were inspired by the beauty and diversity of mathematical sciences. The lectures included “Introduction to Machine Learning” by Senior Research Scientist Akinomi Tanaka, “Principles of Biological Growth and Evolutionary Game Theory” by Senior Research Scientist Ryosuke Iritani, and “Spheres and Dimensions” by Research Scientist Taketo Sano. Through these sessions, the students experienced stimulating learning opportunities beyond their regular classroom studies. Many students commented that the visit was “very helpful in thinking about future career paths” and “opened new perspectives on the joy of mathematics.” This program successfully provided a valuable opportunity for the students to deepen their understanding and interest in mathematical sciences.
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2025-10-01
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Farewell message from Tomoya Naito
Our colleague, Tomoya Naito, has left iTHEMS at the end of September 2025 to join the Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo as a Project Assistant Professor. We are grateful for his many contributions during his time with us and wish him every success in his new position. Here is a message from Tomoya: I first joined the Quantum Hadron Physics Laboratory (Hatsuda Lab.) at the Nishina Center in June 2017 as a student trainee, and from that time I also began attending iTHEMS activities. In April 2022, I officially became a member of iTHEMS as an SPDR, and from April to September 2025 I was a JSPS PD. During these three and a half years (or unofficially, more than eight years!), I really enjoyed being a member of iTHEMS. Although I was often away on business trips in the last two and a half years, I have always appreciated the activities of iTHEMS. My research is on low-energy nuclear physics and quantum many-body problems using density functional theory. Only a few people in iTHEMS are working in this field, but I had many opportunities to learn about other areas such as physics, mathematics, mathematical biology, and machine learning. These experiences gave me new knowledge and even led to new research topics. In particular, during the pandemic, I was not officially a member of iTHEMS, but I still joined many activities and had many discussions with iTHEMS colleagues. These experiences strongly influenced my current research direction. From this April, iTHEMS has been expanding and the atmosphere is also changing. It was a great honor to be a member during such an important period. In October 2025, I moved to the Graduate School of Engineering, the University of Tokyo, as a Project Assistant Professor. Since RIKEN is still geographically close, I would like to continue joining iTHEMS activities, and I look forward to further interactions with everyone. Finally, I would like to express my sincere appreciation to all the researchers and assistants of iTHEMS for their kind support.
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2025-09-04
Hot TopicFarewell message from Seishiro Ono
Our colleague, Seishiro Ono, has left iTHEMS at the end of August 2025 to join the Division of Condensed Matter Theory, The Institute for Solid State Physics (ISSP), The University of Tokyo as an Assistant Professor. We are grateful for his contributions and wish him every success in his new position. Here is a message from Seishiro: I joined iTHEMS in April 2023 as a Special Postdoctoral Researcher, and as of August 31, I have left iTHEMS to start my new position as a Research Associate at the Institute for Solid State Physics, the University of Tokyo. I would like to express my deepest gratitude to all members and staff at iTHEMS. Without such a supportive environment, I would not have been able to devote myself entirely to my research over the past two and a half years. I believe that iTHEMS is a truly unique research institute, and I have been continually impressed by its inspiring and researcher-friendly environment since I first joined. I sincerely hope to stay in touch, and I look forward to seeing you again in the near future. Once again, thank you very much for all your support in every respect.
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2025-08-26
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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
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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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