RIKEN Interdisciplinary Theoretical and
Mathematical Sciences Program

Review on Physics-Driven Learning for Inverse Problems Published in Nature Reviews Physics

Nature Reviews Physics recently published a review paper on ”Physics-driven learning for inverse problems in quantum chromodynamics”, from DEEP-IN working group led by Lingxiao Wang (Research Scientist, iTHEMS), including Tetsuo Hatsuda (Program Director, iTHEMS). The authors explore how combining deep learning techniques with physics-driven designs significantly improves the extraction of accurate physical properties from complex QCD phenomena. Highlighting applications such as lattice QCD calculations and studies of hadron interactions, neutron stars, and heavy-ion collisions, the review emphasizes the benefits of embedding physical priors into machine learning models and suggests broader potentials to general physics problems.

2025-03-06

RIKEN-Nara Women's University Joint Diversity Promotion Workshop 2025 on March 3, 2025

On March 3 and 4, a total of 19 students from various courses at Nara Women's University—including mathematics, physics, chemistry, biological sciences, and environmental sciences (comprising first-year, second-year, and third-year undergraduate students, as well as first-year master's students)—visited RIKEN. During their visit, they toured several research facilities, including the RIBF Facility at the RIKEN Nishina Center (RNC), the RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS), the Laboratory for Sensorimotor Integration at the RIKEN Center for Brain Science (CBS), the Photonics Control Technology Team at the RIKEN Center for Advanced Photonics (RAP), and the Molecular Bioregulation Research Team at the RIKEN Center for Sustainable Resource Science (CSRS). At each laboratory, the students had the opportunity to engage with cutting-edge research up close, observe experimental equipment, and ask researchers about their work. In the evening, they participated in a networking session with RIKEN researchers, where they explored research topics in depth through iTHEMS members' poster presentations. This interactive session also provided insights into the daily lives and career paths of researchers, offering students valuable inspiration from the research environment. This diversity promotion initiative is a collaborative project between the Faculty of Science at Nara Women's University and the RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS), conducted under the auspices of the RIKEN Diversity Promotion Office. It is organized alongside a series of lectures at Nara Women's University and is planned to continue in the coming years.

2025-03-06

Farewell message from Jeffrey Fawcett

Our colleague, Jeffrey Fawcett will move on to a new career as a Chief Scientist at Regional Fish Institute, Ltd. as of March 1st, 2025. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Jeffrey Fawcett: <i>I will be moving to Kyoto to work at a company called Regional Fish from March. I will also most likely have a joint position at Kyoto University at a lab funded by the company. The company was started a few years ago mostly be people from Kyoto University, Graduate School of Agriculture, where I did my study, and specializes in breeding and developing fish and aquatic species using genome editing and various other techniques. My task will mainly be to perform genomic data analysis for the company, although I will also have some freedom to pursue my own research. I am looking forward to the new challenge to utilize my expertise and work for a company whose I mission I can identify with.</i> <i>I have been in iTHEMS for exactly 7 years, which say how much I enjoyed and appreciated the setup of iTHEMS. I remember some people telling me its their first time meeting a biologist, whereas I never imagined I would ever have the opportunity to enjoy talks on pure mathematics and theoretical physics. I would like to thank all the people involved in iTHEMS and hopefully I will be able to visit iTHEMS from time to time and keep up the connection.</i>

2025-02-25

Who Is at Higher Risk of Progression from Acute Liver Injury to Acute Liver Failure?

A collaborative research group, including Professor Shingo Iwami (Visiting Scientist, iTHEMS / Professor, Graduate School of Science, Nagoya University), has applied artificial intelligence (AI) technology to clinical research. Through joint research, they discovered that patients with acute liver injury can be classified into three groups based on their treatment response. Furthermore, they successfully developed the world's first AI model capable of predicting which group a patient belongs to using clinical data such as initial blood test results. For more details, please visit Kyushu University’s website via the related links.

2025-02-10

Make it worth Weyl: engineering the first semimetallic Weyl quantum crystal

An international research team, including Ching-Kai Chiu (Senior Research Scientist, iTHEMS) and led by the Strong Correlation Quantum Transport Laboratory of the RIKEN Center for Emergent Matter Science (CEMS) has achieved a world-first by realizing an ideal Weyl semimetal, marking a major breakthrough in quantum materials research. Weyl fermions emerge as quantum excitations of electrons in crystals and are predicted to exhibit exotic electromagnetic properties. However, previous Weyl materials were often overshadowed by unwanted electronic states, making it difficult to observe pure Weyl fermion behavior. The team successfully engineered an ideal Weyl semimetal by precisely controlling the composition of the topological semiconductor (Cr,Bi)₂Te₃, eliminating irrelevant electronic states. Published in Nature, this work opens new possibilities for terahertz (THz) light devices and next-generation electronics. For more details, please refer to the related link.

2025-01-29

Farewell message from Liang Zhang

Our colleague, Liang Zhang, has returned to the Shanghai Institute of Applied Physics at the University of Chinese Academy of Sciences to complete his PhD thesis. We will all miss him and wish him the very best of luck in successfully defending his thesis ! Here is a message from Liang Zhang: <i>I joined iTHEMS in January 2023 as a joint student and completed my two-year journey here in January 2025. I initially joined iTHEMS to study lattice QCD and the HAL QCD method, and I am deeply grateful to Hatsuda-san and Doi-san for guiding me into this fascinating field. However, I soon realized that my experience at iTHEMS extended far beyond my original purpose. For example I had a discussion with Namba san on chiral symmetry breaking which is studied in both particle physics and cosmology. It left an immediate impression that physics is so universal other than reading such sentences in textbooks. And the interdisciplinary energy at iTHEMS constantly amazed me. When I first came here I always struggled to pinpoint people’s major. In some seminars, theoretical physicists gave a biology talk (like Christy)! I vaguely feel like there is a group theory for nature which can be expressed to different representations, biological, mathematical, physical, etc. Is this what the “i” in iTHEMS means?</i> <i>At last I would like to thank everyone in iTHEMS again for my two-year experience here. This experience gives me a great impulse to expand the possibilities of my future research life. iTHEMS’s uniqueness lies in its boundless possibilities. And I dearly hope our paths will cross again!</i>

2025-01-24

Farewell message from Lucy McNeill

Our colleague Lucy McNeill has moved on to a new career as a Hakubi Assistant Professor at The Hakubi Center for Advanced Research, Kyoto University as of January 16, 2025. We all will miss her and wish her the best of luck in her latest endeavor. Here is a message from Lucy McNeill: <i>During my 1 year at iTHEMS as a postdoctoral researcher, I was presented with opportunities to further both my own research and professional development at every turn. I am especially grateful for iTHEMS directors and colleagues' support in starting the "asymptotics in astrophysics" iTHEMS study group, ample chances to travel abroad to share my work, and the frequent international workshops organised at iTHEMS. In particular, workshops co-hosted with RIKEN-Berkeley left this lasting impression on me; that new stellar astrophysics and supernova physics paradigms are creatively and efficiently conceived when physicists, mathematicians and data scientists join forces to solve longstanding astrophysical puzzles. iTHEMS is such a special place where those necessary first interactions are regularly facilitated, and I am sad to leave. But... "I'll be back"!</i>

2025-01-17

Farewell message from Yantao Wu

Our colleague Yantao Wu will move on to a new career as a faculty member at Institute of Physics, Chinese Academy of Sciences as of January 10, 2025. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Yantao Wu: <i>I joined iTHEMS in June 2021 as a RIKEN-Berkeley fellow, and have stayed here for three years and a half now. iTHEMS is a precious rare place in the academic world, where there seems to be no responsibility, no one telling you what to do, and infinite space for travel; where there seems to be a curious mind on every subject and every question ought to be asked. The interdisciplinary nature of the group has forever left an imprint on me, and I will always remember the vivid biological facts and mathematical tricks that I have learned here. Entering as a condensed matter physicist and leaving as a condensed matter physicist, my heart will always have a spot for the particle theory which I have learned from here. It has been an unexpected, yet very pleasant mix. Sadly, it appears that every gathering ends somewhere, and I need to leave this warm and protective bubble to a new place, to really enter the grown world of independent research and start my own group. iTHEMS will always remain as a source of lasting encouragement. I will move to the Institute of Physics, Chinese Academy of Sciences in Beijing to start a faculty position. If you ever want to visit, please let me know you are from iTHEMS and I will make you a cup of tea (amidst taking you to the great wall and covering your travel costs.) </i>

2025-01-10

Discovery of Measurement-Induced Spectral Phase Transition in Quantum Systems

A collaborative research team, including Ryusuke Hamazaki (Senior Research Scientist, iTHEMS / RIKEN Hakubi Team Leader, Nonequilibrium Quantum Statistical Mechanics RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research (CPR)), has discovered a spectral phase transition in quantum systems under measurement. This research is expected to bridge the gap between two seemingly distinct phenomena: the recently emerging field of “measurement-induced phase transitions in nonequilibrium quantum systems" and the long-studied "phase transitions in equilibrium quantum systems." By discovering the analogy between these transitions, this work paves the way for a deeper understanding of quantum many-body systems. Using a method known as Lyapunov analysis, the team demonstrated the existence of spectral phase transitions in quantum systems under measurement. Furthermore, they found that the critical point of these spectral phase transitions coincides with the critical point of entanglement transitions. For more details, please refer to the related link.

2025-01-10

Ancient DNA unlocks new understanding of migrations in the first millennium AD

A new study published in Nature reveals waves of human migration across Europe during the first millennium AD using a more precise method of analysing ancestry with ancient DNA. Led by Leo Speidel, ECL Unit Leader at RIKEN iTHEMS, formally a Sir Henry Wellcome postdoctoral researcher at the Francis Crick Institute and UCL, alongside Pontus Skoglund at the Francis Crick Institute, this study reports a new data analysis method called Twigstats. Applied to over 1500 ancient genomes, the new approach reveals previously unknown details of migrations in Europe during the first millennium AD (year 1 to 1000), encompassing the Iron Age, the fall of the Roman Empire, the early medieval ‘Migration Period’ and the Viking Age. The new approach can be applied to populations across the world and may enable researcher to reveal more missing pieces of the puzzle in future. Please refer to the press release by the Francis Crick Institute for further details.

2025-01-02

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?

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