# Hot Topic

## Coffee Meeting on Oct.19

2018-10-25

At the weekly coffee meeting on Oct.19(Fri.), Hiroki Kodama (AIMR/iTHEMS) gave a nice explanation on the properties of "flat functions" which often appear in mathematics and physics. He also told us an interesting story about the reference in the arXiv paper below.

Reference

# Upcoming Events

## Seminar

### Assembly rules and a theory for invasion and extinction in minimal food webs

October 29 at 15:00 - 18:00, 2018

Prof. Namiko Mitarai (Niels Bohr Institute, Denmark)

We propose a theory of the evolution of a minimal food web by sequential invasion of new species [1]. Our theory is based on the standard generalized Lotka-Volterra equations, where basal species compete through resource depletion [2]. The considered food webs are “minimal”, as each species only feeds on a single resource, leading to a hierarchical, tree-like food web [1,3]. We prove that at each invasion step there is one uniquely determined outcome: either the invader peacefully coexists with the residents and resources are re-distributed; the invader is eliminated; or one or several of the resident species are removed in a uniquely defined extinction cascade.

At the end of either of these processes the resulting food web relaxes to a globally stable (and feasible) steady state. We break down the essence of our theory in the conceptual “invasion extinction model” (IEM), which allows us to analytically compute the persistence time and the extinction size distribution.

Venue: Seminar Room #160, 1F Main Research Building, RIKEN

Event Official Language: English

## Seminar

### Population genetics of duplicated genes

November 1 at 15:30 - 18:00, 2018

Prof. Hideki Innan (SOKENDAI)

Venue: Seminar Room #160, 1F Main Research Building, RIKEN

Event Official Language: English

## Workshop

### Spintronics: from electrons to quarks (iTHEMS-CEMS Joint Meeting)

November 7 at 10:00 - 17:30, 2018

Program:

10:00-10:15 T. Hatsuda (RIKEN) “Opening”

10:15-10:45 S. Maekawa (RIKEN) “Introduction to Spintronics”.

10:45-11:45 M. Matsuo (KITS, Beijing) “Spintronics phenomena in non-inertial frames” (Review)

13:30-14:30 M. Hongo (Riken) “Introduction to chiral transport phenomena” (Review)

14:30-15:00 Y. Hidaka (RIKEN) “Non-Equilibrium Quantum Transport of Chiral Fluids”

15:30-16:00 Y. Tsutsumi (RIKEN) “Spin-Vorticity Coupling in Liquid He”.

16:00-16:30 T. Takiwaki (NAOJ) “Chiral magnetohydrodynamic turbulence in core-collapse supernovae”

16:30-17:30 Discussion (and Closing by T. Hatsuda)

Venue: Seminar Room #160, 1F Main Research Building, RIKEN

Event Official Language: Japanese

## Math Lecture

### Theory of Operator Algebras (5th)

November 8 at 13:30 - 15:00, 2018

Dr. Yosuke Kubota (Research Scientist, iTHEMS)

Venue: Seminar Room #160, 1F Main Research Building, RIKEN

Event Official Language: Japanese

## Colloquium

### The 6th MACS colloquium

November 8 at 15:00 - 17:30, 2018

Dr. Chikara Furusawa (Team Leader, Laboratory for Multiscale Biosystem Dynamics, RIKEN Center for Biosystems Dynamics Research)

Dr. Ken Takai (Program Director, Extremobiosphere Research Program, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC))

15:00 ティータイム

15:15 「生物の状態変化をどのように記述すべきか：実験室進化と理論解析」古澤 力氏

16:30 「では、教えてくれ。生命の起源の’生命’とはなんのことだ。’生命’ が何かを知らずに、生命の起源を研究していると言うのか？（海原雄山風に）」高井 研氏

The 6th MACS colloquium supported by iTHEMS. It will be broadcasted to Wako, but if you can join the colloquium physically in Kyoto, that would be better. iTHEMS provides good cakes/cookies at Kyoto!

Venue: Lecture room #401, Graduate School of Science Building No 6, Kyoto University

Event Official Language: Japanese

## Seminar

### The 28th QCD Club

November 9 at 15:00 - 17:00, 2018

Prof. Kazuyuki Kanaya (Professor, Institute of Pure and Applied Sciences, University of Tsukuba)

Title: Application of a gradient flow method to thermodynamics of QCD with dynamical quarks

Language: Japanese or English

Venue: #433, Main Research Building, RIKEN

Event Official Language: English

## Workshop

### Workshop on Recent Developments of Chiral Matter and Topology

December 6 - 9, 2018

The aim of this workshop is to gather researchers of high-energy and condensed-matter physics working on chiral Matter and Topology, to exchange ideas and establish collaborations to tackle unsolved issues and carry out future extensions. The workshop expects to welcome 40-60 participants who are interested in the aforementioned topics.

Organizers:

Tomoki Ozawa, Tetsuo Hatsuda (RIKEN iTHEMS)

Di-Lun Yang (RIKEN Nishina Center; YITP, Kyoto)

Chang-Tse Hsieh (Kavli IPMU / ISSP, the Univ. of Tokyo)

Jiunn-Wei Chen, Guang-Yu Guo (National Taiwan Univ.)

Hsiang-Nan Li (Academia Sinica)

Venue: National Taiwan University, Taipei, Taiwan

Event Official Language: English

## Math Lecture

### Theory of Operator Algebras (6th)

December 20 at 15:30 - 17:00, 2018

Dr. Yosuke Kubota (Research Scientist, iTHEMS)

Title: An introduction to operator algebras

Abstract: Operators are linear maps from a (usually an infinite dimensional) linear space (most frequently the Hilbert space) to itself, which is like matrices of infinite degree. Operators form an algebra by obvious addition and multiplication. Operators appear in most of the fields in mathematics, in algebra, in geometry, in analysis, ... Some of the key words at the beginning of these lectures are "spectral theory" "operator algebras" "Tomita-Takesaki theory". These lectures are for non-professional people.

Venue: Seminar Room #160, 1F Main Research Building, RIKEN

Event Official Language: Japanese

## Symposium

### The 7th International Symposium on Data Assimilation (ISDA2019)

January 21 - 24, 2019

The symposium will focus on the cross-cutting issues shared in broad applications of data assimilation from geoscience to various physical and biological sciences. In particular, the symposium will enhance discussions among researchers with various background on, for example, non-Gaussian and nonlinear data assimilation problems, Big Data Assimilation (BDA), high-performance computation (HPC), Uncertainty Quantification (UQ), advanced intelligence (AI) and machine learning, multi-scale and multi-component treatments, observational issues, and mathematical problems.

Abstract Submission Deadline: October 14, 2018 at 11:59 p.m. UTC

Registration Deadline: December 16, 2018 at 11:59 p.m. UTC

Submission/Registration Fee: Free

Venue: 6F auditorium, Computational Science Research Building, R-CCS, Kobe Campus, RIKEN

Event Official Language: English

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