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iTHEMS Weekly News Letter

Seminar Report

Biology Seminar by Dr. Hiroshi Yokota on June 3, 2020


In the 6th biology seminar, Hiroshi Yokota (iTHEMS fellow at Kyoto University) talked about his theoretical work on the energy of chromosome loop structure (collaborative work with Masashi Tachikawa). Through the modeling, he talked about the possibility that the chromosome loop structure may occur due to ATP hydrolysis. His work will stimulate future debate over the source of the energy needed for chromosome loops to occur. Great talk, Hiroshi!
-Ryosuke Iritani

Upcoming Events


Dr. Masaru Hongo thumbnail

iTHEMS theoretical physics seminar

Field theoretical approach to relativistic hydrodynamics

June 12 at 13:00 - 14:30, 2020

Dr. Masaru Hongo (Visiting Scientist (Academia), iTHEMS)

Hydrodynamics is a low-energy effective theory of a conserved charge density, which describes a long-distance and long-time behavior of many-body systems. It is applicable not only to a non-relativistic weakly-interacting dilute gas but also a relativistic strongly-interacting dense liquid like a quark-gluon plasma. The main purpose of this seminar is to explain how we can derive the hydrodynamic equation from the underlying field-theoretical description of systems [1-3]. Our derivation is based on the recent development of non-equilibrium statistical mechanics, and we show that the procedure to derive hydrodynamic equations is similar to the so-called renormalized/optimized perturbation theory. Also, to describe transport phenomena in local thermal equilibrium, we give a path-integral formula for a thermodynamic functional, which results in the emergence of thermally induced curved spacetime [2]. These results enable us to derive hydrodynamic equation based on quantum field theories.

Event Official Language: English


Math Seminar

Information geometry of operator scaling

June 17 at 16:00 - 18:10, 2020

Dr. Tasuku Soma (Research Associate, Graduate School of Information Science and Technology, The University of Tokyo)

Matrix scaling is a classical problem with a wide range of applications. It is known that the Sinkhorn algorithm for matrix scaling is interpreted as alternating e-projections from the viewpoint of classical information geometry.

Recently, a generalization of matrix scaling to completely positive maps called operator scaling has been found to appear in various fields of mathematics and computer science, and the Sinkhorn algorithm has been extended to operator scaling.

In this study, the operator Sinkhorn algorithm is studied from the viewpoint of quantum information geometry through the Choi representation of completely positive maps. The operator Sinkhorn algorithm is shown to coincide with alternating e-projections with respect to the symmetric logarithmic derivative metric, which is a Riemannian metric on the space of quantum states relevant to quantum estimation theory. This talk is based on joint work with Takeru Matsuda.

Venue: via Zoom

Event Official Language: English

Special Lecture

Dr. Yoh Iwasa thumbnail

iTHEMS Intensive Course: "Adaptive strategies of organisms, their mathematical bases"

June 18 - 26, 2020

Dr. Yoh Iwasa (Senior Advisor, iTHEMS)

Living systems exhibit features distinct from nonliving physical systems: their structure and behaviors appear to be chosen adaptive. They are the outcomes of evolution. Mathematical formalisms developed in engineering and social sciences (e.g. control theory, game theory, evolutionary game theory) are sometimes very useful in biology.

This course is composed of five sessions (including the colloquium) illustrating the use of different mathematics in modeling particular aspects in biology. [1] Sex expression and sex allocation of marine organisms; [2] Dynamic optimization models for growth and reproduction; [3] Synchronized reproduction of trees (coupled chaotic system); [4] Cancer as a mini-evolutionary process. (colloquium); [5] Evolution of cooperation and illegal logging in tropical forests.

[1] June 18 (Thu) 13:30-15:00
”Sex expression and sex allocation of marine organisms”
keeping gonad of unused sex, dwarf males, environmental sex determination, temperature dependent sex determination in reptiles

[2] June 19 (Fri) 13:30-15:00
"Dynamic optimization models for growth and reproduction“
timing of flowering for annual plants, shoot/root balance, annuals versus perennials, monocarpy (one time reproduction), storage as an insurance, plant defense with alkaloid and age dependence

[3] June 25 (Thu) 13:30-14:30
"Masting, synchronized reproduction of trees: Coupled chaotic system”
masting of trees, coupled chaotic systems, empirical tests, evolution of masting/nonmasting

[4] June 25 (Thu) 15:00-16:30 (Colloquium)
"Cancer as a mini-evolutionary process”
chromosomal instability, acquisition of drug resistance, enhanced cancer risk for companion animals

[5] June 26 (Fri) 13:30-15:00
"Evolution of cooperation”
social evolution by indirect reciprocity, illegal logging in tropical forests and corruption

Venue: via Zoom

Event Official Language: English


DMWG seminar

Dark Matter Heating vs. Rotochemical Heating in Old Neutron Stars

June 22 at 16:00 - 17:00, 2020

Prof. Koichi Hamaguchi (Associate professor, School of Science, The University of Tokyo)

*Detailed information about the seminar refer to the email

Venue: via Zoom

Event Official Language: English

Paper of the Week

Week 2 of June


Title: d∗(2380) dibaryon from lattice QCD
Author: Shinya Gongyo, Kenji Sasaki, Takaya Miyamoto, Sinya Aoki, Takumi Doi, Tetsuo Hatsuda, Yoichi Ikeda, Takashi Inoue, Noriyoshi Ishii

Title: Universality classes of non-Hermitian random matrices
Author: Ryusuke Hamazaki, Kohei Kawabata, Naoto Kura, Masahito Ueda

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