iTHEMS Weekly News Letter

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Farewell message from Dr. Yoshiyuki Inoue


Hello colleagues. I am Yoshiyuki Inoue, a senior research scientist here at iTHEMS. I am leaving iTHEMS and joining Osaka University as an associate professor. It has been almost three years since I came here. I would like to thank all the iTHEMS friends for your kind support and help, especially Hatsuda-san, Tada-san, and assistants. The open research atmosphere allowed me to expand my research area a lot, e.g., collaboration with other RIKEN researchers. I believe the interdisciplinary and academic freedom mind in iTHEMS is essential for future research. I will bring and spread this iTHEMS spirit in Osaka. Even after moving to Osaka, I will keep visiting our precious research place, iTHEMS (the coffee room, maybe?). I wish future success of iTHEMS research activity.


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Dr. Yosuke Kubota received 2020 Takebe Katahiro Prize


It is our greatest pleasure to inform you that our iTHEMS colleague, Yosuke Kubota received 2020 Takebe Katahiro Prize for Encouragement of Young Researchers from The Mathematical Society of Japan (MSJ) for his contribution to the "Applications of operator K theory in geometry”. This prize was established by MSJ in honor of the renowned Japanese Mathematician in Edo period, Katahiro Takeba (1664 –1739).

Research News

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RIKEN NEWS: To produce the best racehorse


The article written by Dr. Jeffrey Fawcett, Senior Research Scientist, was published in this month's RIKEN News. He wrote about the genetics of Thoroughbred horses and his research using genomic data of Japanese Thoroughbreds.

Seminar Report

Biology Seminar by Dr. Miki Ebisuya on July 17, 2020


In 1638, Galileo Galilei proposed “the square-cube law”: the ratio of two volumes is greater than the ratio of their surfaces. This law enables us to understand why large animals like elephants need longer time to cool their body temperature than small ones like human. On July 17th, Miki Ebisuya at European Molecular Biology Laboratory (EMBL) explained why human needs longer time to develop her/his body than mouse, at the iTHEMS seminar. In fact, the speed of the segment formation ("taisetsu" in Japanese) of human is twice or three times as slow as that of mouse. By combining state-of-the-art experiments and a model with two variables, her group discovered that the difference of tempos is due to the difference of biochemical parameters. The talk was clear and enjoyable. And it was accessible to the diverse audience. As a mathematician asked during the talk, their discovery raises a new fundamental question about why reactions in human are slower than those in mouse. The question might be also answered by the collaboration between biology and mathematics in a future.

Seminar Report

Biology Seminar by Dr. Masashi Tachikawa on September 9, 2020


On 9th September, Masashi Tachikawa (Kyoto University) gave us a talk on adaptive dynamics as a framework for evolutionary dynamics. He first gave us a quick overview for modeling evolution, and then introduced adaptive dynamics toolbox and pairwise invasibility plots to visualize trait-substitution processes towards evolutionarily singular points. He finally talked about how to capture evolutionary branching (two morphs emerging) using envelope with a trait value being tuned as-if a parameter. We all excitedly learned a lot from this talk. Thank you, Masashi!
-Ryosuke Iritani

Upcoming Events


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The 2nd Heidelberg-Kyoto-RIKEN Workshop, Medicine and Math

September 18 - 19, 2020

Dr. Tetsuo Hatsuda (Program Director, iTHEMS)
Prof. Takashi Sakajo (Senior Visiting Scientist, iTHEMS / Professor, Department of Mathematics, Kyoto University / Senior Visiting Scientist, Prediction Science Laboratory, RIKEN Cluster for Pioneering Research (CPR))
Prof. Motomu Tanaka (Professor, Heidelberg University / Professor, Center for Integrative Medicine and Physics, Kyoto University Institute for Advanced Study (KUIAS))

Venue: via Online

Event Official Language: Japanese


STAMP Seminar

Potential Toolkit to Attack Nonperturbative Aspects of QFT -Resurgence and related topics-

September 7 - 25, 2020

Dr. Aleksey Cherman (University of Minnesota, USA)
Prof. Gerald Dunne (University of Connecticut, USA)
Prof. Mithat Unsal (North Carolina State University, USA)
Dr. Toshiaki Fujimori (Keio University)
Dr. Yasuyuki Hatsuda (Rikkyo University)
Dr. Masazumi Honda (Kyoto University)
Dr. Okuto Morikawa (Kyushu University)
Dr. Naohisa Sueishi (Nagoya University)
Dr. Masahito Yamazaki (Kavli IPMU, The University of Tokyo / The University of Tokyo)

Recently, there have been significant developments in theoretical techniques/frameworks to tackle non-perturbative aspects of quantum field theory (QFT) such as the resurgence theory, the Lefschetz thimble method, ’t Hooft anomaly matching, and novel lattice setups. Such developments are still growing very rapidly and making fruitful connections not only among physicists involved in fields with broad energy scales but also with mathematicians. These developments would enable us to unveil rich and exciting physics of QFT in the non-perturbative regime. It is of primary importance to hold a workshop for researchers in various fields related to the topics to get together and overview/share the recent progresses, to discuss future directions, and to seek for possible new collaborations bridging various fields of physics/mathematics.

Venue: YITP (Kyoto University), Zoom, and Mozilla hubs

Event Official Language: English

External Event

Perspective of nuclear physics in the 21 century

September 27 at 13:30 - 17:00, 2020

Dr. Tetsuo Hatsuda (Program Director, iTHEMS)
Prof. Hiroyoshi Sakurai (Director, RIKEN Nishina Center for Accelerator-Based Science (RNC))
Prof. Naohito Saito (Director, J-PARC Center)
Prof. Takaaki Kajita (Director, The Institute for Cosmic Ray Research (ICRR), The University of Tokyo)


Venue: via YouTube Live

Event Official Language: Japanese


DMWG Seminar

The Uchuu Simulations: Data Release 1 and Dark Matter Halo Concentrations

October 1 at 14:00 - 15:00, 2020

Dr. Tomoaki Ishiyama (Associate Professor, Institute of Management and Information Technologies)

We introduce the Uchuu suite of large high-resolution cosmological N-body simulations. The largest simulation, named Uchuu, consists of 2.1 trillion dark matter particles in a box of 2.0 Gpc/h. The highest resolution simulation, called Shin-Uchuu, consists of 262 billion particles in a box of 140 Mpc/h. Combining these simulations we can follow the evolution of dark matter haloes (and subhaloes) spanning from dwarf galaxies to massive galaxy cluster hosts. We present basic statistics, dark matter power spectra and halo (subhalo) mass function, to demonstrate the huge dynamic range and superb statistics of the Uchuu simulations. From the analysis of the evolution of the power spectra we conclude that our simulations are accurate enough from the Baryon Acoustic Oscillations up to very small scales. We also provide parameters of a mass-concentration model, which describes the evolution of halo concentrations, that reproduces our simulation data within 5% error for haloes with masses spanning nearly eight orders of magnitude at redshift 0<z<14. We make publicly available various N -body products, as part of Uchuu Data Release 1, on the Skies & Universes site. We also plan to release gravitational lensing maps, mock galaxy, X-ray cluster and active galactic nuclei catalogues in the near future.

Venue: via Zoom

Event Official Language: English


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Forefront of Modern Science: Frontiers in Mathematics, Astronomy, Physics, Biology and Computation

October 2 at 16:20 - 17:50, 2020

Dr. Tetsuo Hatsuda (Program Director, iTHEMS)
Dr. Yuka Kotorii (Visiting Scientist, iTHEMS / Associate Professor, Mathematics Program, Graduate School of Advanced Science and Engineering, Hiroshima University / Visiting Scientist, Mathematical Analysis Team, RIKEN Center for Advanced Intelligence Project (AIP))
Dr. Shigehiro Nagataki (Deputy Program Director, iTHEMS / Chief Scientist, RIKEN Astrophysical Big Bang Laboratory)
Dr. Makiko Nio (Senior Researcher, RIKEN Nishina Center for Accelerator-Based Science (RNC))
Dr. Ryosuke Iritani (Research Scientist, iTHEMS)
Dr. Ai Niitsu (Postdoctoral Researcher, Theoretical Molecular Science Laboratory, RIKEN)
Dr. Shigenori Otsuka (Research Scientist, iTHEMS / Research Scientist, Data Assimilation Research Team, RIKEN Center for Computational Science)
Dr. Emi Yukawa (Assistant Professor, Department of Physics, Faculty of Science Division I, Tokyo University of Science)

Venue: Changed to Zoom

Event Official Language: Japanese

Paper of the Week

Week 2 of September


Title: 3D modeling from the onset of the SN to the full-fledged SNR: Role of an initial ejecta anisotropy on matter mixing
Author: Antonio Tutone, Salvatore Orlando, Marco Miceli, Sabina Ustamujic, Masaomi Ono, Shigehiro Nagataki, Gilles Ferrand, Emanuele Greco, Giovanni Peres, Donald C. Warren

Title: Snowmass 2021 Letter of Interest: The GRAMS Project: MeV Gamma-Ray Observations and Antimatter-Based Dark Matter Searches
Author: Tsuguo Aramaki, Jonathan Asaadi, Yuto Ichinohe, Yoshiyuki Inoue, Georgia Karagiorgi, Jon Leyva, Reshmi Mukherjee, Hirokazu Odaka, Kerstin Perez, William Seligman, Satoshi Takashima, Naomi Tsuji, Hiroki Yoneda

Title: The index theorem of lattice Wilson--Dirac operators via higher index theory
Author: Yosuke Kubota

Title: Area law of non-critical ground states in 1D long-range interacting systems
Author: Tomotaka Kuwahara, Keiji Saito

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