RIKEN Interdisciplinary Theoretical and
Mathematical Sciences Program

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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.

About iTHEMS

Upcoming Events


iTHEMS Math Seminar

The Conley index of topological dynamical systems

December 3 at 16:00 - 18:00, 2021

Prof. Yosuke Morita (Assistant Professor, Department of Mathematics, Kyoto University)

The study of topological dynamical systems, i.e. continuous self-homeomorphisms (or continuous flows) on topological spaces, is important in both pure mathematics and applications. To each isolated invariant subset of a topological dynamical system, we can assign an invariant called the Conley index, which is (roughly speaking) a based space that describes the dynamics around the isolated invariant subset. It is used not only in the study of topological dynamical systems themselves but also in Manolescu’s construction of the Seiberg-Witten-Floer homotopy type (a spectrum-valued (3+1)-dimensional TQFT). In this talk, I am planning to explain a new construction of Conley indices, which is entirely non-homotopical and uses only basic general topology. *Please contact Keita Mikami or Hiroyasu Miyazaki's mailing address to get access to the Zoom meeting room.

Venue: via Zoom

Event Official Language: English


iTHEMS Math Seminar

Generalized Bernoulli process and computation of proportional areas for Venn diagram

December 8 at 16:00 - 18:00, 2021

Dr. Ryosuke Iritani (Research Scientist, iTHEMS)

*For detailed information about the seminar, please refer to the email.

Venue: via Zoom

Event Official Language: English


iTHEMS Biology Seminar

Selective inference for testing trees and edges in hierarchical clustering and phylogeny

December 9 at 10:00 - 11:00, 2021

Prof. Hidetoshi Shimodaira (Professor, Graduate School of Informatics, Kyoto University / Team Leader, Mathematical Statistics Team, RIKEN Center for Advanced Intelligence Project (AIP))

Bootstrap resampling is quite useful for computing “confidence values” or “p-values” of trees and edges. However, they are biased and may lead to false positives (too many wrong discoveries) or false negatives (too few correct discoveries) depending on the “curvature” of the boundary surface of a hypothesis region in the data space. In addition, we face the issue of selection bias because we tend to use the dataset twice for hypothesis selection and its evaluation. I will explain these two types of bias and show methods to adjust the confidence values.

Venue: via Zoom

Event Official Language: English


DMWG Seminar

The long-lived particle search of the FASER experiment

December 15 at 17:00 - 18:00, 2021

Prof. Hidetoshi Otono (Assistant Professor, Research Center for Advanced Particle Physics, Kyushu University)

*For detailed information about the seminar, please refer to the email.

Venue: via Zoom

Event Official Language: English

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Seeking a Kyoto University Program-Specific Assistant Professor (female)

Deadline: December 24, 2021

Kyoto University Program-Specific Assistant Professor (female), one position. Seeking a female Program-Specific Assistant Professor who will work for the collaboration between the Kyoto University MAthematics-based Creation of Science (MACS) Program and RIKEN iTHEMS. During her term, she will also serve as a Visiting Scientist at RIKEN iTHEMS.

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.

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Latest News


Seminar Report

iTHEMS Biology Seminar by Prof. Catherine Beauchemin on October 14, 2021

Defective interfering virus particles (DIPs) are viruses that are defective in a very specific way that allows them to out-compete standard, non-defective virus. It is difficult to count DIPs because they can look too similar to standard virus. So instead, people are counting them based on their effect on suppressing the standard virus population. In this talk, C. Beauchemin explained the basic biology of virus replication, what are DIPs, and how they compete with standard virus. She presented her group's mathematical model (ordinary differential equation) that describes co-infection competition with DIPs and standard virus. She also showed applications of the mathematical model to show how experiments to count DIPs can give incorrect results, and proposed some solutions.


Person of the Week

Self-introduction:Tomoki Nosaka

My name is Tomoki Nosaka. I have joined RIKEN iTHEMS as a research part-time worker in November 2021. My research field is the theoretical physics. I have been trying to reveal new aspects of M-theory, which is supposed to be the theory of everything though still being mysterious, by means of the supersymmetric gauge theories, matrix models and their integrability. Recently I am also interested in the quantum information theory and the various notions of chaos in quantum many-body systems which are found to be closely related to the black hole physics. I am looking forward to interacting with people in iTHEMS working with various research interests and finding a new direction of research out of it.


Paper of the Week

Week 4, November 2021

Title: Factorizing Wormholes in a Partially Disorder-Averaged SYK Model Author: Kanato Goto, Kenta Suzuki, Tomonori Ugajin arXiv: http://arxiv.org/abs/2111.11705v1

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Upcoming Visitors


Prof. Katsuki Aoki

Research Assistant Professor, Yukawa Institute for Theoretical Physics, Kyoto University

Term: November 30 - December 4, 2021

Visiting Place: RIKEN Wako Campus

Dr. Keigo Shimada

Ph.D. Student, Department of Physics, Tokyo Institute of Technology

Term: December 1, 2021

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