Volume 140

iTHEMS Weekly News Letter

Hot Topic

Tetsuo Hatsuda thumbnail

Report on the online discussion, "The Usefulness of 'Useless' Knowledge"

2021-03-02

On August 22 last year, academist.Inc, and RIKEN iTHEMS held an online discussion entitled "Tetsuo Hatsuda × Yoshinori Ohsumi × Sayaka Oki Online Discussion: The Usefulness of 'Useless' Knowledge" with the aim of discussing the future of basic science research. Please refer to the related links for the online discussion of the day.

Hot Topic

Ryosuke Iritani thumbnail

Biology and mathematics: What it would be like to be crazy about both

2021-03-02

Dr. Ryosuke Iritani (Research Scientist, iTHEMS) writes frankly on the website SURI-JOSHI about why he chose his current field. Don't miss it!

Research News

Shigehiro Nagataki thumbnail
Masaomi Ono thumbnail

RIKEN Research: Supernova had a missing companion star

2021-03-01

The massive star that exploded to form the supernova known as Cassiopeia A most likely had a companion star that has yet to be spotted, a spectro-scopic analysis by RIKEN astro-physicists suggests.

Reference

  1. Sato, T., Yoshida, T., Umeda, H., Nagataki, S., Ono, M., Maeda, K., Hirai, R., Hughes, J. P., Williams, B. J. & Maeda, Y., A subsolar metallicity progenitor for Cassiopeia A, the remnant of a type IIb supernova, The Astrophysical Journal 893, 49 (2020), doi: 10.3847/1538-4357/ab822a

Research News

Takemasa Miyoshi thumbnail

RIKEN Research: RIKEN and JAXA collaborate on real-time rainfall forecasts

2021-03-01

Researchers from RIKEN, Chiba Univer-sity, the University of Tokyo and the Japan Aerospace Exploration Agency (JAXA) have used a combination of satellite data and supercomputer simulations to offer five-day rainfall forecasts over the Internet covering the globe. Dr. Takemasa Miyoshi (iTHEMS/R-CCS) commented in the article.

Upcoming Events

Seminar

iTHEMS Biology Seminar

Microeconomics of metabolism

March 10 (Wed) at 10:00 - 11:00, 2021

Jumpei Yamagishi (Ph.D. Student, Kaneko Laboratory, The University of Tokyo)

Metabolic behaviors of proliferating cells are often explained as a rational choice to optimize cellular growth rate. In contrast, microeconomics formulates consumption behaviors as optimization problems of utilities. We pushed beyond this analogy to precisely map metabolism onto the theory of consumer choice.

We thereby revealed the correspondence between and a general mechanism for mysteries in biology and economics: the Warburg effect, a seemingly-wasteful but ubiquitous phenomenon where cells favor aerobic glycolysis over more energetically-efficient respiration, and Giffen behavior, the unexpected consumer behavior where a good is demanded more as its price rises. The correspondence implies that respiration is counterintuitively stimulated when its efficiency is decreased by drug administration.

This “microeconomics of metabolism” will serve as a macroscopic phenomenology to predict the metabolic responses against environmental operations. In particular, it offers a universal relationship between the metabolic responses against drug administrations and changes in nutrient availability.

Venue: via Zoom

Event Official Language: English

Internal Meeting

iTHEMS NOW & NEXT for FY2020

March 11 (Thu) at 9:30 - 14:30, 2021

Seminar

iTHEMS Math Seminar

The Green-Tao theorem for number fields

March 22 (Mon) at 16:00 - 18:10, 2021

Wataru Kai (Assistant Professor, Mathematical Institute, Tohoku University)

5, 11, 17, 23, 29 are prime numbers which form an arithmetic progression of length 5. A famous theorem of Ben Green and Terence Tao in 2008 says there are arbitrarily long arithmetic progressions of prime numbers. Algebraic number theorists are also interested in more general numbers like square roots of integers. Recently, Mimura, Munemasa, Seki, Yoshino and I have established a generalization of the Green-Tao theorem in such a direction.

In the first 50 minutes of my talk, I would like to explain some background and technology behind the Green-Tao theorem. In the second half after a break, I explain the concept of number fields to formulate our generalization of their result. I will also discuss how one of the new difficulties, which I call the norm vs length conflict, is handled by a technique called Geometry of Numbers.

*Please contact Keita Mikami or Hiroyasu Miyazaki's mailing address to get access to the Zoom meeting room.

Venue: via Zoom

Event Official Language: English

Seminar

Math-Phys Seminar

Self-adjoint extension in quantum mechanics and non-Rydberg spectra of one-dimensional hydrogen atom

April 13 (Tue) at 16:00 - 18:10, 2021

Takuju Zen (Professor, School of Environmental Science and Engineering, Kochi University of Technology)

We offer a beginner’s guide to the functional-analytical techniques in quantum mechanics, and cover its application to the 1D Coulomb problem. It is shown that the wave function at the diverging point of the Coulomb potential is mathematically described by three-parameter family of generalized connection conditions. A scheme is devised to physically implement the generalized conditions, which provides the way to experimentally realize non-Rydberg spectra in 1D Hydrogen atom.

Schedule:
Part 1, Self-adjoint extension of Hilbert space operator
Part 2, 1D Coulomb problem

Venue: via Zoom

Event Official Language: English

Person of the Week

Takeru Yokota thumbnail

Self-introduction: Takeru Yokota

2021-03-04

My name is Takeru Yokota. I joined iTHEMS in March 2021. My research field is theoretical physics. I have been interested in the development of nonperturbative frameworks to describe many-body systems, such as the functional renormalization group (FRG). In particular, I have challenged to establish a new framework based on the combination of FRG and density functional theory, which is another powerful method used for various systems including nuclear systems and condensed matter systems, and involved in the application to electrons, nucleons, and classical liquids. I am looking forward to new developments of research emerged from the interaction with researchers from various fields in iTHEMS.

Person of the Week

Yuta Sekino thumbnail

Self-introduction: Yuta Sekino

2021-03-04

I am Yuta Sekino, a JSPS fellow who joined iTHEMS on March 1, 2021. I am a theoretical physicist studying physics of ultracold atoms. My main research interest is universal properties of many-body systems as well as transport phenomena. I am currently working on atomic gases in spatially one dimension and spin transport. At iTHEMS, I hope to broaden my research horizon through discussions with researchers in various fields.

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