iTHEMS Weekly News Letter

Event Schedule

Events for the 1st week of August 2021


Wednesday, August 4, 13:30- Information Theory SG Seminar
Friday, August 6, 12:30- Coffee Meeting
Friday, August 6, 16:00- iTHEMS Math Seminar

Research News

RIKEN RESEARCH: Smoking-gun evidence for neutrinos’ role in supernova explosions thumbnail
Dr. Shigehiro Nagataki thumbnail

RIKEN RESEARCH: Smoking-gun evidence for neutrinos’ role in supernova explosions


Supernova explosions are sustained by neutrinos from neutron stars, a new observation suggests.
Shigehiro Nagataki (Deputy Program Director, iTHEMS) were interviewed in the article.

Research News

iTHEMS research activities and researchers were featured in "RIKEN 2021"


iTHEMS research activities and researchers were featured in several articles in "RIKEN 2021".

p.8-9: A Theoretical Description of the Inside of an Evaporating Black Hole and a Closer Look at Its True Nature (Yuki Yokokura)
p.10-11: Image only (Don Warren and Naomi Tsuji)
p.20-21: Tackling the Mysteries of Biology with Mathematical Science Models (iTHEMS Biology Seminar Study Group)

Upcoming Events

Special Lecture

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Tetsuo Hatsuda x Kunihiko Nakata x Yoshihiro Kozuka x Kenshiro Sadaka‏ x Aiko Teranishi - Will Useless Knowledge Change the Future? - What is the Black Hole Recorder?

August 2 at 20:00 - 22:00, 2021

Dr. Tetsuo Hatsuda (Program Director, iTHEMS)
Mr. Yoshihiro Kozuka (ADK Holdings Inc.)
Mr. Kenshiro Sadaka (ADK Holdings Inc.)
Ms. Aiko Teranishi (President and CEO,

This event will feature a thorough explanation of the "Black Hole Recorder," a device inspired by the latest black hole theory.
Free of charge. Registration required.

Venue: via Zoom

Event Official Language: Japanese


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iTHEMS Math Seminar

From Yang-Mills theory to enumerative geometry on Calabi-Yau 4-folds

August 6 at 16:00 - 18:10, 2021

Dr. Yalong Cao (Research Scientist, iTHEMS)

Yang-Mills theory was studied from mathematical perspectives in the 1970s by Atiyah and his collaborators (notably Drinfeld, Hitchin, Singer). Subsequent breakthroughs were made on dimensions 3 and 4 by Floer and Donaldson (based on deep analytic results obtained by Uhlenbeck and Taubes) in the 1980s. In 1996, Donaldson and Thomas proposed to study Yang-Mills theories on dimensions bigger than 4. In higher dimensions, the analytic method is limited and algebro-geometric method is heavily used instead. This powerful tool usually enables us to compute partition functions and lead to amazing links to other invariants in enumerative geometry, e.g. Gromov-Witten and Gopakumar-Vafa invariants. In this talk, I will review some of these inspiring stories and discuss how my works on Calabi-Yau 4-folds fit into them.

Venue: via Zoom

Event Official Language: English


iTHEMS Colloquium

Finding Gravitational Waves from the Early Universe

September 27 at 16:00 - 17:30, 2021

Prof. Eiichiro Komatsu (Director, Max Planck Institute for Astrophysics, Germany)

The Cosmic Microwave Background (CMB) gives a photographic image of the Universe when it was still an “infant”. We have been using it to test our ideas about the origin of the Universe. The CMB research told us a remarkable story: the structure we see in our Universe such as galaxies, stars, planets, and eventually ourselves originated from tiny quantum fluctuations in the period of the early Universe called cosmic inflation. While we have accumulated strong evidence for this picture, the extraordinary claim requires extraordinary evidence. The last prediction of inflation that is yet to be confirmed is the existence of primordial gravitational waves whose wavelength can be as big as billions of light years. To this end we have proposed to JAXA a new satellite mission called LiteBIRD, whose primary scientific goal is to find signatures of gravitational waves in the polarisation of the CMB. In this presentation we describe physics of gravitational waves from inflation, and the LiteBIRD proposal.

Venue: via Zoom

Event Official Language: English

Person of the Week

Dr. Yalong Cao thumbnail

Self-introduction: Yalong Cao


I am a mathematician doing research on algebraic geometry, differential geometry and mathematical physics. I am particularly interested in understanding Yang-Mills theory on Calabi-Yau 4-folds and how it is interacted with enumerative geometry. I am eager to understand how such theory could lead to unexpected relations with other areas. It is my great pleasure to join RIKEN iTHEMS and I am looking forward to having exciting discussions with you.

Paper of the Week

Week 5, July 2021


Title: A Fundamental Plane in X-ray Binary Activity of External Galaxies
Author: Yoshiyuki Inoue, Kiyoto Yabe, Yoshihiro Ueda

Title: Three-body crossover from a Cooper triple to bound trimer state in three-component Fermi gases near a triatomic resonance
Author: Hiroyuki Tajima, Shoichiro Tsutsui, Takahiro M. Doi, Kei Iida

Title: A mathematical model of network elastoplasticity
Author: Hiroki Kodama, Ken'ichi Yoshida

Title: On regular $^*$-algebras of bounded linear operators: A new approach towards a theory of noncommutative Boolean algebras
Author: Michiya Mori

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