RIKEN Interdisciplinary Theoretical and
Mathematical Sciences Program

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

iTHEMS Science Outreach Workshop 2024 was held on November 15-17, 2024

On November 15-17, we had Meeting on Outreach of RIKEN iTHEMS 2024 @Sendai & Zoom. This year as the last year the meeting was held at TOKYO ELECTRON House of Creativity 3F, Lecture Theater, Katahira Campus, Tohoku University. It was organized by RIKEN iTHEMS and Mathematical Science Center for Co-creative Society of Tohoku University and co-organised by Tohoku Forum for Creativity, Organization for Research Promotion, Tohoku University and RIKEN CPR, Prediction Science Laboratory. There were 39 people participated at TOKYO ELECTRON House of Creativity and 16 more by zoom. There were 20 talks at the venue and 2 talks by zoom. There were 2 posters, one photo exhibition. There were really a variety of thought around the past and the future of mathematics. Some of highlights are: talks concerning about causality from designers and physisists; about teaching mathematics in Art University; about the preparation of "Mathematics Connecting to the World: One S&T poster for Every Household"; etc. 7 talks were given by journalists and 1 by MEXT. The on-site participants consist of 10+1 members from RIKEN, 14+3 from universities and institutes, and 12+5 journalists (at venue + by zoom). We organized a social gathering on the first evening which was successful. We thank very much for the help of Tohoku University for the warm hospitality. By the success of this meeting, we hope the continuation of Journalist in residence program and this workshop next year. Reported by Takashi Tsuboi

2024-12-24

Hadrons and Hadron Interactions in QCD -- Experiments, Effective theories, and Lattice -- (HHIQCD2024) was held from Oct. 14 to Nov. 15, 2024

On Oct. 14 (Mon) - Nov. 15 (Fri), a long-term workshop "Hadrons and Hadron Interactions in QCD -- Experiments, Effective theories, and Lattice -- (HHIQCD2024)" was held at Yukawa Institute for Theoretical Physics (YITP), Kyoto University. The week of Oct. 28 (Mon) - Nov. 2 (Fri) was held as "Nishinomiya-Yukawa symposium". The workshop was sponsored by YITP and supported by RIKEN-iTHEMS and several JSPS/JST programs. We had 193 participants from all over the world, with most of them attending in-person. There were 64 invited talks and 49 contributed talks. The international school, "Introduction to QCD and related topics", was also held and 5 lectures were given. The purpose of this HHIQCD2024 workshop was to bring researchers in lattice QCD, various effective field theories and also experimentalists together and make extensive discussions on hadron physics. Furthermore, the workshop also focused on formal developments of quantum field theories and frontiers of first-principle calculations (quantum computation and tensor network methods). The workshop expected to bring a new direction of researches to understand the nature of QCD. This long-term workshop was a "stay-and-discuss" style workshop in a relaxed atmosphere, where each participant was encouraged to stay long. With this style, participants had intensive discussions with other participants, and even started new collaborations during the workshop. Presentation slides can be downloaded from the HHIQCD2024 web page.

2024-12-17

Exploring Quantum Gravity Theories and Contributing to the Future - Yasunori Nomura

Professor Yasunori Nomura, a theoretical physicist at the University of California, Berkeley, has been staying at RIKEN iTHEMS for about two months each summer since last year, conducting research. Despite his busy schedule, Nomura is also actively engaged in outreach activities. We spoke with him about his life journey and thoughts on his research activities. Please see the full article via the related link.

2024-12-04

Expanding New Medical Possibilities From Microbial Research - Daiki Kumakura

Daiki Kumakura, is a Ph.D. student at the Graduate School of Life Science, Hokkaido University. He is also a Junior Research Associate (JRA) at RIKEN iTHEMS, where he conducts his research. We asked him about the advantages of conducting research at iTHEMS as a student and his aspirations for the future. Please see the full article via the related link.

2024-12-04

Farewell message from Shingo Gibo

Our colleague Shingo Gibo will move on to a new career as senior researcher at Institute for Basic Science (IBS), South Korea as of December 1, 2024. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Shingo Gibo: <i>I joined iTHEMS in September 2018 and spent six years as a postdoctoral researcher at iTHEMS. During this time, I have theoretically studied biological oscillations with Kurosawa-san. Additionally, I collaborated on interdisciplinary research on waveforms in circadian clocks with physicists, Hatsuda-san and Kunihiro-san. I would like to thank all the members for the valuable discussions and support. I have learned a lot and truly enjoyed my time at iTHEMS. From December, I will be moving to Institute for Basic Science (IBS) in South Korea as a senior researcher. Thank you for the great six years and see you again!</i>

2024-11-26

To Continue Being a Researcher - Misako Tatsuuma

What processes lead to the formation of planets? — Research Scientist Misako Tatsuuma aims to theoretically answer this question. Describing herself as "indecisive at times but fundamentally a perfectionist," Tatsuuma adds, "I consider strategies carefully before acting." This approach applies not only to her research but also to her private life. What are these strategies? Please see the full article via the related link.

2024-11-18

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?

Recipe for soup of quarks and gluons

A subjective view on what is a quantum effect

Mathematical aspects of the entropic uncertainty relation

Forming black holes from stars

Singularity Theorems

Resurgence: making sense out of non-convergent series

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

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

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

Exploring Quantum Spacetime

Classical simulations of quantum computers

When a Cretan says all Cretans are liars

Physical and local observables in gravitational theory

Can you hear the shape of a drum?

Quantum many-body physics with cold atoms

complexity in non-unitary dynamics of photons

Physics Through the Looking Glass

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

Evolution and our daily rhythms

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

Comparison between conventional computers and quantum computers

A glimpse of enumerative geometry

Message-passing algorithms for graphical models

Canonical form of tensor networks in one and two dimensions

The basics of topological band theory

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

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

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

Morse theory and Floer theory

Knot theory and topological semimetals

On Dark Matter

Odd couples of interdisciplinary research

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

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

In Search of Pc pentaquark - Simulate Hadron Interactions with FUGAKU