iTHEMS Weekly News Letter

Seminar Report

Biology Seminar by Dr. Lukasz Kusmierz on August 5, 2020

2020-08-05

On 5th August, Ph.D. Lukasz Kusmierz ( RIKEN Center for Brain Science ) gave a talk at the iTHEMS Biology Seminar. Dr. Kusmierz introduced us to his work that modeling of heavy tails in the distribution of synaptic weights in the brain. His modeling, called "Cauchy network" which is based on the Cauchy distribution, has been successful in recreating biologically distributions. It could serve as a useful framework for checking the effects of synaptic heavy tails in various scenarios. His research will be a major step forward in the future of neuroscience. Thank you very much, Lukasz!

Upcoming Events

Seminar

iTHEMS Theoretical Physics Seminar

Lefschetz-thimble inspired analysis of the Dykhne–Davis–Pechukas method and an application for the Schwinger Mechanism

August 21 at 13:00 - 14:30, 2020

Dr. Takuya Shimazaki (Researcher, Hadron Theory Group, The University of Tokyo)

Dykhne–Davis–Pechukas (DDP) method is a common approximation scheme for the transition probability in two-level quantum systems, as realized in the Landau–Zener effect, leading to an exponentially damping form comparable to the Schwinger pair production rate. We analyze the foundation of the DDP method using a modern complex technique inspired by the Lefschetz-thimble method. We derive an alternative and more adaptive formula that is useful even when the DDP method is inapplicable. As a benchmark, we study the modified Landau–Zener model and compare results from the DDP and our methods. We then revisit a derivation of the Schwinger Mechanism of particle production under electric fields using the DDP and our methods. We find that the DDP method gets worse for the Sauter type of short-lived electric pulse, while our method is still a reasonable approximation. We also study the Dynamically Assisted Schwinger Mechanism in two methods.

Venue: via Zoom

Event Official Language: English

Special Lecture

Tetsuo Hatsuda × Yoshinori Ohsumi × Sayaka Oki Online Discussion: "The Usefulness of 'Useless' Knowledge" Presented by iTHEMS & academist

August 22 at 13:00 - 15:30, 2020

Dr. Tetsuo Hatsuda (Program Director, iTHEMS)
Prof. Yoshinori Ohsumi (Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology)
Prof. Sayaka Oki (Graduate School of Economics, Department of Socio-Economic System, Nagoya University)

学問の世界で大切なのは、研究者の「なぜ」「不思議だな」という好奇心です。研究者は自らの好奇心をもとに想像力を膨らませ、さまざまな仮説を立て、それを実験、観測、調査で検証し、最終的には理論的に体系づけていきます。このような基礎研究で得られた知識は、私たちの生活に直接「役に立つ」ものではありません。しかし、5年、10年といった期間ではなく、100年、1000年単位で考えると、基礎研究は確実に世の中の役に立ち、私たちはその恩恵にあずかっています。

現在、国内外の大学や研究機関には、企業の経営戦略からきている「選択と集中」の考えが入ってきており、好奇心に基づいた研究を進めることが難しくなっています。令和時代において、私たちはどのように基礎研究を継続させていくことができるのでしょうか。今回のイベントでは、各分野で活躍する3名の研究者にお越しいただき、登壇者の一人でもある初田哲男氏監訳の書籍タイトル『「役に立たない」科学が役に立つ』をテーマとした議論を進めていきます。

Venue: via Zoom

Event Official Language: Japanese

Lecture

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

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 August

2020-08-13

Title: Artificial magnetic field for synthetic quantum matter without breaking time reversal symmetry
Author: Tomoki Ozawa
arXiv: https://arxiv.org/abs/2008.02412

If you would like to cancel your subscription or change your email address,
please let us know via our contact form.