RIKEN Interdisciplinary Theoretical and
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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

Seminar

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

Seminar

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

Seminar

ABBL/iTHEMS Astro Seminar

Magnetic field dependence of neutrino-driven core-collapse supernova models

December 10 at 14:00 - 15:00, 2021

Prof. Jin Matsumoto (Assistant Professor, Graduate School of Science and Technology Keio Institute of Pure and Applied Sciences, Keio University)

Massive stars can explode and release huge energy (typically 10^51 erg) at the end of their life. It is one of the most energetic explosions in the Universe and is called a core-collapse supernova. The impact of the magnetic field on the explosion mechanisms of the core-collapse supernova is a long-standing mystery. Recently, we have updated our neutrino-radiation-hydrodynamics supernova code (3DnSNe, Takiwaki et al. 2016) to include magnetohydrodynamics (MHD). Using this code, we have performed three-dimensional MHD simulations for the evolution of non-rotating stellar cores focusing on the difference in the magnetic field of the progenitors. Initially, 20 and 27 solar mass pre-supernova progenitors are threaded by only the poloidal component of the magnetic field, which strength is 10^10 (weak) or 10^12 (strong) G. We find that the neutrino-driven explosion occurs in both the weak and strong magnetic field models. The neutrino heating is the main driver for the explosion in our models, whereas the strong magnetic field slightly supports the explosion. In my talk, I will introduce the details of this mechanism.

Venue: via Zoom

Event Official Language: English

Seminar

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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Opportunities

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

2021-12-02

Paper of the Week

Week 1, December 2021

Title: Flavor number dependence of QCD at finite density by the complex Langevin method Author: Yusuke Namekawa, Yuhma Asano, Yuta Ito, Takashi Kaneko, Hideo Matsufuru, Jun Nishimura, Asato Tsuchiya, Shoichiro Tsutsui, Takeru Yokota arXiv: http://arxiv.org/abs/2112.00150v1 Title: Emergence of the rho resonance from the HAL QCD potential Author: Yutaro Akahoshi, Sinya Aoki, Takumi Doi arXiv: http://arxiv.org/abs/2111.15138v1 Title: Color superconductivity in a small box: a complex Langevin study Author: Shoichiro Tsutsui, Yuhma Asano, Yuta Ito, Hideo Matsufuru, Yusuke Namekawa, Jun Nishimura, Asato Tsuchiya, Takeru Yokota arXiv: http://arxiv.org/abs/2111.15095v1 Title: Perturbative predictions for color superconductivity on the lattice Author: Takeru Yokota, Yuhma Asano, Yuta Ito, Hideo Matsufuru, Yusuke Namekawa, Jun Nishimura, Asato Tsuchiya, Shoichiro Tsutsui arXiv: http://arxiv.org/abs/2111.14578v1 Title: QHC21 equation of state of neutron star matter -- in light of 2021 NICER data Author: Toru Kojo, Gordon Baym, Tetsuo Hatsuda arXiv: http://arxiv.org/abs/2111.11919v1 Title: Flux tube profiles in two-color QCD at low temperature and high density Author: Katsuya Ishiguro, Kei Iida, Etsuko Itou arXiv: http://arxiv.org/abs/2111.13067v1

2021-12-02

Event Schedule

Events for the 2nd week of December 2021

Wednesday, December 8, 16:00– 18:00 iTHEMS Math Seminar Thursday, December 9, 10:00– 11:00 iTHEMS Biology Seminar Friday, December 10, 12:30- Coffee Meeting

2021-12-01

Seminar Report

ABBL/iTHEMS Astro Seminar by Dr. Hirotaka Yoshino on November 12, 2021

Dr. Yoshino gave us a talk on his recent work on axions around rotating black holes. He showed results of his numerical simulations of so-called “superradiant instability” in which an axion field around a rotating black hole extracts the energy of the black hole. These results suggest that every astrophysical black hole is expected to wear a cloud of the axion. Reported by Akira Mizuta (ABBL, RIKEN)

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