Featured News
Mathematics and Physics: Topology, Insulators and My Research Life
Dr. Tomoki Ozawa (Visiting Scientist, iTHEMS) writes on the website "SURI-JOSHI" about topological insulators and his research life and daily life. Please see the related link for the article.
2021-09-22
A New Mechanism to Explain Multispecies Coexistence in Plants - Evolutionary Rescue Caused by the Evolution of Self-Fertilization before Flowering
Koki Katsuhara (Assistant Professor, Okayama University; at the time: Kobe University), Yuuya Tachiki (Assistant Professor, Tokyo Metropolitan University), Ryosuke Iritani (Research Scientist, iTHEMS; at the time: University of California, Berkeley, University of Exeter) and Atsushi Ushimaru (Professor, Kobe University) performed simulations using an individual-based model and found that in two plant species that share the same species of pollinator and are in competition, evolutionary rescue occurs in which the evolution of higher self-fertilization rates in the rarer species results in an increase in population size, thereby promoting long-term coexistence between the two species. The results of this study add a new theory to explain why multiple flowering species can coexist in the same place, and also provide a new perspective for the evolution of diverse reproductive strategies in plants. Understanding the mechanisms that create and maintain plant diversity, which supports the basis of terrestrial ecosystems, is essential not only for understanding the origin of biodiversity, but also for forming a sustainable society in harmony with ecosystems, and is an important knowledge in both basic and applied aspects. For more information, please visit the Okayama University website at the related link.
2021-09-17
Supercomputer Predicts Fascinating New Particle Charmed Di-Omega - A new page toward solving the puzzle of the 6-quark states has been added -
An international collaboration including Takuya Sugiura (Postdoctoral Researcher, iTHEMS) , Tetsuo Hatsuda (Program Director, iTHEMS), and Takumi Doi (Senior Research Scientist, Quantum Hadron Physics Laboratory, RNC) has theoretically predicted the existence of a new particle called Charmed Di-Omega which consists of six charm quarks. To read more, please see the related link (in Japanese).
2021-08-31
RIKEN-Vancouver Joint Workshop on Quantum Computing was held on August 24-25, 2021
RIKEN-Vancouver Joint Workshop on Quantum Computing was held online on August 24-25. The main aim of this workshop is that the quantum people in RIKEN (iTHEMS and RQC) and Vancouver (Quantum BC) get together online to discuss scientific activities and explore future collaborations. There were altogether 164 registrations (90 from Japan, 62 from Canada and 12 from other countries). 12 scientific talks were presented together with 3 introduction to iTHEMS, RQC and Quantum BC. From iTHEMS, Jason Chang, Etsuko Itou, and Takumi Doi gave talks respectively on the Schroedinger equation, the U(1) gauge theory and combinatorial optimization. After each session, there were one-hour breakout sessions, so that people can ask further questions to the speakers, which worked very well. The workshop was an excellent first step toward a close tie between RIKEN quantum activities and Vancouver quantum activities.
2021-08-27
Nihon Keizai Shimbun: Utilizing the Power of Quantum Computers in Combination
Dr. Hirotaka Irie (iTHEMS Visiting Scientist (Industry)) was interviewed in the Nihon Keizai Shimbun. He talks about the "hybrid type" that combines the best parts of conventional computers and quantum computers. Please see the related link for details.
2021-08-23
RIKEN RESEARCH: Smoking-gun evidence for neutrinos’ role in supernova explosions
Supernova explosions are sustained by neutrinos from neutron stars, a new observation suggests. Shigehiro Nagataki (Deputy Program Director, iTHEMS) were interviewed in the article.
2021-07-29
iTHEMS research activities and researchers were featured in "RIKEN 2021"
iTHEMS research activities and researchers were featured in several articles in "RIKEN 2021". p.8-9: A Theoretical Description of the Inside of an Evaporating Black Hole and a Closer Look at Its True Nature (Yuki Yokokura) p.10-11: Image only (Don Warren and Naomi Tsuji) p.20-21: Tackling the Mysteries of Biology with Mathematical Science Models (iTHEMS Biology Seminar Study Group)
2021-07-27
iTHEMS Science Outreach Workshop 2021 was held on July 11-12, 2021
On July 11 and 12, we had Journalist in Residence Workshop 2021 on Zoom. This year as last year, Tambara Institute of Mathematical Sciences of the University of Tokyo is closed because of COVID-19 and we again organized it on Zoom. The participants included more than 20 journalists, more than 20 participants from RIKEN and 10 from universities. 9 iTHEMS members mainly explained their working field and recent important achievements to the nonspecialists. There were 24 talks in total in a variety of fields. The discussion among the participants continued with joy in the evening of July 11 in ZOOM. We hope to organize it next year, in principle face to face and including remote participants by online.
2021-07-15
RIKEN RESEARCH: Physics modeling of viral spread between cells
Prof. Catherine Beauchemin (Deputy Program Director, iTHEMS) was featured in the summer issue of RIKEN RESEARCH 2021. Describe your role at RIKEN - I first joined RIKEN in 2016 as a senior visiting scientist at iTHES, the predecessor of the Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) program. In 2020, I became one of four iTHEMS deputy program directors. I am in a field I call ‘virophysics’; the application of physics methods to virology. Primarily, I construct computer and mathematical models to explain the experimental observations made when viruses infect cell cultures. In biology, such knowledge is usually advanced through experimental trial and error, but physics modeling can help streamline this process. To read more, please see the related links.
2021-06-28
RIKEN NEWS: What is the Significance of Basic Research?
Program Director Tetsuo Hatsuda is interviewed on the RIKEN website and summer issue of RIKEN NEWS 2021. How did the universe begin? Why does matter exist? What is the origin of life? Basic research, which pursues such fundamental questions, is difficult for the general public to understand because it does not necessarily lead to immediate practical applications. We asked Tetsuo Hatsuda, Program Director (PD) of the Theoretical and Mathematical Sciences Program (iTHEMS), what exactly basic research is. To read more, please see the related link (in Japanese).
2021-06-25
Videos
Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS) is an international research program at RIKEN. It facilitates close collaborations among researchers from different disciplines in theoretical, mathematical and computational sciences. The ultimate goal of iTHEMS is to unravel the mystery of the Universe, matter, and life, as well as to solve key problems in modern society through interdisciplinary approaches.
Program Director: Dr. Tetsuo Hatsuda
Upcoming Events
Today
Nonlinear response in strongly correlated systems
October 20 at 17:00 - 18:15, 2021
Dr. Robert Peters (Lecturer, Department of Physics, Graduate School of Science, Kyoto University)
Nonlinear responses in condensed matter are intensively studied because they provide rich information about materials and hold the possibility of being applied in diodes or high-frequency optical devices [1-4]. While nonlinear responses in noninteracting models have been explored widely, the effect of strong correlations on the nonlinear response is still poorly understood. This talk will introduce a Green's function method to calculate nonlinear conductivities in strongly correlated materials [5-6]. Correlation effects are thereby included by the self-energy of the material. I will then use this method to study the nonlinear conductivities in noncentrosymmetric f-electron systems. The first system is a heavy Fermion system, where a nonreciprocal conductivity appears in the ferromagnetic phase. The nonreciprocal conductivity thereby always occurs perpendicular to the magnetization of the system and has a strong spin dependence, which might be advantageous for spintronic applications. The second system is a model corresponding to the Weyl-Kondo semimetal Ce3Bi4Pd3, in which a giant spontaneous Hall effect without time-reversal symmetry breaking has been observed [7]. This Hall effect can be explained as a nonlinear Hall effect in an inversion-symmetry broken Weyl-semimetal. It has been shown that the nonlinear Hall effect is related to the Berry curvature dipole [4]. Our study shows that the magnitude of the experimentally observed nonlinear Hall effect can be explained by the strong correlations inherent in this f-electron material [8]. *Detailed information about the seminar refer to the email.
Venue: via Zoom
Event Official Language: English
Can social issues be solved by mathematical science? -attempts and challenges
October 26 at 10:00 - 17:00, 2021
Dr. Tetsuo Hatsuda
(Program Director, iTHEMS)
Dr. Masato Wakayama
(Vice President, Tokyo University of Science)
Prof. Takashi Sakajo
(Professor, Department of Mathematics, Kyoto University)
Prof. Shingo Iwami
(Professor, Division of Biological Science, Graduate School of Science, Nagoya University)
Dr. Hirotaka Irie
(Assistant Manager, DENSO Corporation)
In recent years, the importance of mathematical sciences has been increasingly recognized in various fields, as exemplified by the rapid progress of AI technology and the development of DX (Digital Transformation) in companies. In academia, research centers have been established in fields such as space, materials, life, and medicine, where experts in the mathematical sciences play an important role in research activities in their respective fields. At the same time, the universality of mathematics and the quantitative and predictive nature of data analysis are also being considered useful in industry, and some companies are actively using mathematical science in their own business. Some companies are actively utilizing mathematical science in their business. In this symposium, researchers who are conducting research with the mission of returning research using mathematical science to society and implementing it will gather to discuss, based on the results of their cutting-edge research, "Can social issues be solved with mathematical science? -Attempts and Challenges" and discuss the role of mathematical science in society.
Venue: Hybrid Format (Noyori Conference Hall, Nagoya University and Zoom)
Event Official Language: English
High-Energy Neutrino Astrophysics in the Multimessenger Era
October 28 at 15:00 - 16:30, 2021
Prof. Kohta Murase (Associate Professor, Pennsylvania State University, USA)
The discovery of high-energy cosmic neutrinos opened a new window of astroparticle physics. Their origin is a new mystery in the field, which is tightly connected to the long-standing puzzle about the origin of cosmic rays. I will give an overview of the latest results on high-energy neutrino and cosmic-ray observations, and demonstrate the power of "multimessenger" approaches. In particular, I will show that the observed fluxes of neutrinos, gamma rays, and extragalactic cosmic rays can be understood in a unified manner. I will also highlight the recent developments about astrophysical neutrino emission from supermassive black holes and violent transient phenomena. Possibilities of utilizing high-energy neutrinos as a probe of heavy dark matter may be discussed.
Venue: via Zoom
Event Official Language: English
Opportunities
Seeking a few Postdoctoral Researchers (W21169)
Deadline: Open until filled
Postdoctoral Researcher, a few positions. In particular, we welcome applications from young researchers who are interested in exploring theories of quantum gravity in a broad sense. Currently, Senior Research Scientist Yuki Yokokura is affiliated with iTHEMS, and we expect young researchers with complementary and unique expertise, who are willing to pursue their own ambitious motivation and create synergy among the members.
Seeking a few Postdoctoral Researchers (RIKEN-Berkeley Fellow associated with N3AS) (W21157)
Deadline: Open until filled
Postdoctoral Researcher (RIKEN-Berkeley Fellow associated with N3AS), a few positions. Theoretical works associated with neutrino physics, nucleosynthesis, dense matter and neutron stars, dark matter, astrophysical simulations and related fields.
Seeking a few Postdoctoral Researchers (W21158)
Deadline: Open until filled
Postdoctoral Researcher, a few positions. In particular, the successful applicant(s) are expected to spend at least 50% of their time working with Dr. Ryosuke Iritani carrying out interdisciplinary research addressing fundamental questions in population genetics, phylogenetics, and bioinformatics, by using mathematical and theoretical approach in dynamical systems, stochastic process, statistical physics, and/or information theory. Applicants are expected to have a considerable expertise in those theories.
Seeking a Female Research Scientist or a Female Senior Research Scientist (W21071)
Deadline: Open until filled
Female Research Scientist or Female Senior Research Scientist, a few positions. Seeking a female researcher or a female senior researcher to conduct theoretical research in the fields of natural sciences, mathematical sciences, or humanities and social sciences.
Seeking a Postdoctoral Researcher or Research Scientist (W21003)
Deadline: Open until filled
Postdoctoral Researcher or Research Scientist, a few positions. In particular, the applicant(s) are expected to spend at least 50% of their time carrying out original research developing numerical models to describe biological systems, such as the spread of virus in a cell culture, in collaboration with Dr. Catherine Beauchemin.
Latest News
2021-10-18
ABBL/iTHEMS Astro Seminar by Dr. Nobuya Nishimura on October 15, 2021
At the seminar, there were lots of questions and answers for r-process nucleosynthesis and kilonova events. The speaker presented lots of his excellent works on them, and the audience enjoyed his presentation with curiosity. Reported by Shigehiro Nagataki
2021-10-14
Week 3, October 2021
Title: The genome of Shorea leprosula (Dipterocarpaceae) highlights the ecological relevance of drought in aseasonal tropical rainforests Author: Kevin Kit Siong Ng, Masaki J. Kobayashi, Jeffrey A. Fawcett, Masaomi Hatakeyama, Timothy Paape, Chin Hong Ng, Choon Cheng Ang, Lee Hong Tnah, Chai Ting Lee, Tomoaki Nishiyama, Jun Sese, Michael J. O’Brien, Dario Copetti, Mohd Noor Mat Isa, Robert Cyril Ong, Mahardika Putra, Iskandar Z. Siregar, Sapto Indrioko, Yoshiko Kosugi, Ayako Izuno, Yuji Isagi, Soon Leong Lee, Kentaro K. Shimizu Journal Reference: Commun Biol 4, 1166 (2021) doi: https://doi.org/10.1038/s42003-021-02682-1 Title: Effect of advancing age on the reproductive performance of Japanese Thoroughbred broodmares Author: Jeffrey A. FAWCETT, Hideki INNAN, Takeru TSUCHIYA, Fumio SATO Journal Reference: J. Equine Sci. Vol. 32, No. 2, pp. 31–37 (2021) doi: https://doi.org/10.1294/jes.32.31 Title: Universal relation for supernova gravitational waves Author: Hajime Sotani, Tomoya Takiwaki, Hajime Togashi arXiv: http://arxiv.org/abs/2110.03131v2 Title: Topology and symmetry of circular photogalvanic effect in the chiral multifold semimetals: a review Author: Congcong Le, Yan Sun doi: https://doi.org/10.1088/1361-648X/ac2928 arXiv: http://arxiv.org/abs/2110.03434v1
2021-10-13
Nagisa Hiroshima received the Award for Female Researchers of the University of Toyama
University of Toyama has announced that Nagisa Hiroshima (Visiting Scientist, iTHEMS) received "The Award for Female Researchers of the University of Toyama". Congratulations!