Volume 191

iTHEMS Weekly News Letter

Event Schedule

Events for the 5th week of March 2022

2022-03-25

Wednesday, March 30, 13:30– 15:00 NEW WG Seminar
Thursday, March 31, 10:00- 11:00 iTHEMS Biology Seminar

Hot Topic

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Farewell message from Dr. Akinori Tanaka

2022-03-22

Our colleague Akinori Tanaka moves on to a new carrier at RIKEN AIP as of April 1st. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Akinori Tanaka:

First of all, I would like to thank my colleagues, assistants, and all the people for sharing time in iTHEMS. I really enjoyed discussing and chatting, even though I spent a lot of time online.

In fact, this is the 2nd time for me to leave here. When I started my research as a member of iTHES, not iTHEMS at that time, I was working on theoretical physics. But, in addition to my own research, I also enjoyed chatting with my colleagues and getting new concepts: machine learning and related topics, and it opened up my next career. As a result, I returned to iTHEMS as a machine learning researcher, as you know. It was very surprising for me that all the activities were really sophisticated compared to the ones in iTHES, and I was happy to participate in the activities in information theory study group, SSP workshop, and chatting after the coffee meeting.

Now I leave this message as if this was farewell, but it's not. I will move to RIKEN AIP from this April as a senior research scientist, but hold a post in iTHEMS also. I would like to deepen my thoughts on machine learning from mathematical, biological, and physical perspectives, so I'm happy if all of you discuss/chat with me as I have so far, even after April.

Hot Topic

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Farewell message from Dr. Kanato Goto

2022-03-22

Our colleague Kanato Goto moves on to a new carrier at Kyoto University as of April 1st. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Kanato Goto:

I am leaving iTHEMS to move to Yukawa Institute for Theoretical Physics at Kyoto University. I have been very happy to have had the opportunity to work with you all for the past three years. The experience of discussing with scientists from various fields at iTHEMS is invaluable for my research carrier. The first year I joined iTHEMS, I stayed in the U.S. Regrettably, the Corona disaster struck during my stay, and I was deprived of the opportunity to interact with you all in person, even after returning to Japan. I hope to visit iTHEMS in the near future and discuss you again.
I cannot thank the assistants enough for their great help. Thanks to them, I could devote myself to my research without any inconvenience. Thank you very much, all the iTHEMS members! See you again soon!

Hot Topic

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Farewell message from Dr. Naomi Tsuji

2022-03-22

Our colleague Naomi Tsuji moves on to a new carrier at Kanagawa University as of April 1st. We all will miss her and wish her the best of luck in her latest endeavor. Here is a message from Naomi Tsuji:

Since I joined iTHEMS in April 2020, my research life at iTHEMS completely overlapped with the pandemic. At first, I found it difficult to get to know each other and communicate with the other iTHEMS members through online meeting systems, but gradually it became possible and comfortable to me. I have been working on mainly data analysis of X-ray or gamma-ray observations from astrophysical objects at iTHEMS, a group of theorists. I was glad that some members showed their interest in my study, and it was so exciting and stimulating to discuss about it. I wish I could have more discussion with many of the iTHEMS members in person and hope those days will come in the near future. Until then, let us stay healthy and have good science!

Hot Topic

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Farewell message from Dr. Yukimi Goto

2022-03-22

Our colleague Yukimi Goto moves on to a new carrier at Kyushu University as of April 1st. We all will miss her and wish her the best of luck in her latest endeavor. Here is a message from Yukimi Goto:

It may not be obvious to those in other fields, but iTHEMS is a unique place for Japanese mathematicians. Japanese mathematicians do not have many opportunities to talk with researchers in fields other than their own. I am an applied mathematician, but I did not have a chance to talk casually with physicists at university. After coming to iTHEMS and talking with physicists and biologists, I found that they are very interested in and expect a lot from mathematics. When I talked about my research, they always tried to understand it and asked me what kind of problems we could solve in mathematics. I enjoyed discussing with them, and it motivated me to do research. Although it was only two years and I met most of them online, I am grateful that I had such a wonderful time with them.

Hot Topic

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Farewell message from Dr. Takashi Okada

2022-03-22

Our colleague Takashi Okada moves on to a new carrier at Kyoto University as of April 1st. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Takashi Okada:

I joined iTHEMS in 2018. My main workplace was in Hallatschek group, UC Berkeley. I researched on biophysics & evolutionary dynamics and learned a lot of things there.
I also enjoyed working with iTHEMS members on interdisciplinary projects. I believe that some projects were made possible only by collaboration with wonderful iTHEMS members.
I really appreciate iTHEMS' support during my long-term stay in Berkeley. Thanks to iTHEMS support, I could focus on work without any problems during this pandemic.

From this spring, I am moving to Mochizuki Lab (Kyoto Univ) as a Program-Specific Associate Professor. The scientific atmosphere of ITHEMS is so great, and I hope that I can continue to collaborate with great members in iTHEMS. Let's keep in touch!

Seminar Report

How is mathematics utilized in society? - Exploring the Essence of Mathematical Research Special Lecture by Shigefumi Mori and Takashi Sakajo on March 12, 2022

2022-03-25

On March 12, a zoom discussion by two mathematicians, Takashi Sakajyo (Kyoto U./iTHEMS) and Shigefumi Mori (KUIAS/iTHEMS), was held as an iTHEMS x academist special event "How is mathematics utilized in society?" More than 380 people from academia, schools, and companies have joined online. After the introductory talks on the usefulness of mathematics in modern times by Sakajyo san, and on the beauty and joy of mathematics by Mori san, they had interesting discussions on three topics, the relation between mathematics and society, mathematics education, and how do mathematicians face mathematical problems?

Reported by Tetsuo Hatsuda

Seminar Report

iTHEMS Math Seminar by Dr. Lin Li on March 18, 2022

2022-03-22

In March 18, there was a seminar by Dr. Lin Li. He explained his theoretical research on the control of hurricane. The main difficulty is that the order of the energy of the so large that it is 106 times larger than the energy we could use. To overcome this difficulty, he explained some ideas and his simulation on how his ideas will work.

Reported by Keita Mikami

Upcoming Events

Seminar

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iTHEMS Biology Seminar

Journal Club: Phase separation in a many-component system with random interactions

March 31 (Thu) at 10:00 - 11:00, 2022

Kyosuke Adachi (Special Postdoctoral Researcher, Nonequilibrium Physics of Living Matter RIKEN Hakubi Research Team, RIKEN Center for Biosystems Dynamics Research (BDR))

Several kinds of protein condensates have been observed in living cells, and the liquid-liquid phase separation is regarded as a basic mechanism of the condensate formation. However, given that there are thousands of protein species in a cell, it is not clear how the number and the composition of distinct condensates are controlled. One of the physics approaches to this problem is considering a model of many components with random interactions. In this Journal Club, I will introduce a recent paper [1] that applies random-matrix theory to the phase separation dynamics.

Reference

  1. K. Shrinivas, M. Brenner, Phase separation influids with manyinteracting components, Proc. Natl. Acad. Sci. U.S.A. 118, e2108551118 (2021), doi: 10.1073/pnas.2108551118

Venue: via Zoom

Event Official Language: English

Colloquium

iTHEMS Colloquium

How is turbulence born: Statistical mechanics and ecological collapse in transitional fluids

April 22 (Fri) at 15:00 - 16:30, 2022

Hong-Yan Shih (Assistant Research Fellow, Institute of Physics, Academia Sinica, Taiwan)

The onset of turbulence is ubiquitous in daily life and is important in various industrial applications, yet how fluids become turbulent has remained unsolved for more than a century. Recent experiments in pipe flow finally quantified this transition, showing that non-trivial statistics and spatiotemporal complexity develop as the flow velocity is increased. Combining numerical simulations of the hydrodynamics equations and an effective theory from statistical mechanics, we discovered the surprising fact that fluid behavior at the transition is governed by the emergent predator-prey dynamics, leading to the mathematical prediction that the laminar-turbulent transition is analogous to an ecosystem on the edge of extinction. This prediction demonstrates that the laminar-turbulent transition is a non-equilibrium phase transition in the directed percolation universality class, and provides a unified picture of transition to turbulence in various systems. I will also show our recent progresses on transitional turbulence, including how an extended ecological model with energy balance successfully recapitulates the spatiotemporal patterns beyond the critical point, and the determination of the critical behavior and an emergent novel phase under interactions in the experimental collaboration.

Venue: via Zoom

Event Official Language: English

Paper of the Week

Week 4, March 2022

2022-03-24

Title: Quantum and classical annealing in a continuous space with multiple local minima
Author: Yang Wei Koh, Hidetoshi Nishimori
arXiv: http://arxiv.org/abs/2203.11417v1

Title: Dehn twists and the Nielsen realization problem for spin 4-manifolds
Author: Hokuto Konno
arXiv: http://arxiv.org/abs/2203.11631v1

Title: Neutron star mass formula with nuclear saturation parameters
Author: Hajime Sotani, Hajime Togashi
Journal Reference: Phys. Rev. D 105(6), 063010 (3/2022)
arXiv: http://arxiv.org/abs/2203.09004v1

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