iTHEMS Weekly News Letter

Event Schedule

Events for the 3rd week of October 2021


Tuesday, October 12, 16:00- Quantum Matter Seminar
Friday, October 15, 12:30- Coffee Meeting

Upcoming Events


iTHEMS Math Seminar

Geography of varieties of general type

October 8 at 16:00 - 18:10, 2021

Prof. Chen Jiang (Associate Professor, Shanghai Math Center, Fudan University, China)

We study birational invariants in order to study birational classifications of varieties. Geography is the study of relations among different invariants. We will focus on two fundamental invariants: canonical volume and geometric genus. For surfaces there are classical results such as Miyaoka-Yau inequality and Noether inequality. I will discuss higher dimensional analogue of them, and introduce our recent work on the optimal Noehter inequality for 3-folds joint with Jungkai Chen and Meng Chen.

*Please contact Keita Mikami's mail address to get access to the Zoom meeting room.

Venue: via Zoom

Event Official Language: English


Quantum Matter Seminar

Symmetry-based analysis for unconventional superconductors: Diagnosis of topological and nodal superconductivity

October 12 at 16:00 - 17:15, 2021

Mr. Seishiro Ono (Department of Applied Physics, School of Engineering, The University of Tokyo)

The physics of unconventional superconductors has gained a new dimension in the past decade, thanks to the bloom in the understanding of topological quantum materials. Keeping in mind the success of the symmetry-based diagnosis in the large-scale discovery of topological insulator and semimetal candidates [1], it is natural to ask whether the approach can be generalized to superconducting systems.

In this talk, I provide a unified way to diagnose topology and superconducting nodes in unconventional superconductors. First, I review symmetry-indicator theory for the topological insulators [2]. Also, I also discuss how to generalize the theory to superconductors [3,4,5]. Next, I show that the symmetry-based approach can extensively classify superconducting nodes pinned to high-symmetric momenta [6]. Finally, I show that these results enable us to derive the comprehensive correspondences between pairing symmetries and topological/nodal superconducting nature for each material [7].

*Detailed information about the seminar refer to the email.

Venue: via Zoom

Event Official Language: English


iTHEMS Colloquium

High-Energy Neutrino Astrophysics in the Multimessenger Era

October 28 at 15:00 - 16:30, 2021

Prof. Kohta Murase (Associate Professor, Pennsylvania State University, USA)

The discovery of high-energy cosmic neutrinos opened a new window of astroparticle physics. Their origin is a new mystery in the field, which is tightly connected to the long-standing puzzle about the origin of cosmic rays. I will give an overview of the latest results on high-energy neutrino and cosmic-ray observations, and demonstrate the power of "multimessenger" approaches. In particular, I will show that the observed fluxes of neutrinos, gamma rays, and extragalactic cosmic rays can be understood in a unified manner. I will also highlight the recent developments about astrophysical neutrino emission from supermassive black holes and violent transient phenomena. Possibilities of utilizing high-energy neutrinos as a probe of heavy dark matter may be discussed.

Venue: via Zoom

Event Official Language: English

Person of the Week

Mr. Yixin Guo thumbnail

Self-introduction:Yixin Guo


My name is Yixin GUO, a Junior Research Associate joined in iTHEMS from October 2021. I come from China, and now study in the Doctoral Course at The University of Tokyo. I am majoring in theoretical nuclear physics. I am mainly interested in (but not only) the quantum many-body problem, nuclear structure theory, density functional theory, and nuclear reaction theory. I also have some experience in the accelerator physics. I look forward to exchanging ideas with various researchers from different fields.

Paper of the Week

Week 2, October 2021


Title: Confinement/deconfinement transition in the D0-brane matrix model -- A signature of M-theory?
Author: Georg Bergner, Norbert Bodendorfer, Masanori Hanada, Stratos Pateloudis, Enrico Rinaldi, Andreas Schäfer, Pavlos Vranas, Hiromasa Watanabe

Title: Searching for TeV gamma-ray emission from SGR\,1935+2154 during its 2020 X-ray and radio bursting phase
Author: H.E.S.S. Collaboration (Naomi Tsuji)
Journal Reference: ApJ 919, 106-114 (2021)

Title: Heavy-quark spin polarization induced by Kondo effect under magnetic field
Author: Daiki Suenaga, Yasufumi Araki, Kei Suzuki, Shigehiro Yasui

Title: Yu-Shiba-Rusinov states in a superconductor with topological Z2 bands
Author: Ching-Kai Chiu, Ziqiang Wang

Title: Design strong anomalous Hall effect via spin canting in antiferromagnetic nodal line materials
Author: Congcong Le, Claudia Felser, Yan Sun
Journal Reference: PhysRevB.104.125145(2021)

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