In this seminar, I will give an introduction to topological photonics, that is, the study of topological band structures and resulting topological phenomena in photonic systems. I will first review basic concepts of topological band structures, and then explain what it means to realize topological band structures in photonic systems. I will particularly emphasize some important differences with respect to solid-state electron systems. I then present some of my own works in topological photonics, such as the synthetic dimensions in photonic systems, which allows one to explore models and phenomena in high dimensions including the four-dimensional quantum Hall effect.

15:00- Teatime
15:15- Talk by Dr. Keisuke Fujii (Kyoto University)
16:30- Talk by Prof. Takao Hirajima (Kyoto University)

The 5th MACS colloquium supported by iTHEMS. It will be broadcasted to Wako by Skype, but if you can join the colloquium physically in Kyoto, that would be better. iTHEMS provides good cakes/cookies at Kyoto!

This is the first joint workshop between iCeMS (Kyoto Univ.) and iTHEMS (RIKEN). The WS is co-hosted by KUIAS (Kyoto Univ.), iTHEMS (RIKEN) and MACS Program (Kyoto Univ.). By exploring the forefront of experimental and mathematical biology, this workshop aims to stimulate novel research directions in these areas and strengthen the connection between Kyoto Univ. and RIKEN. Those who plan to attend the "get-together", please register before June 22 (Fri.) noon.

Co-hosted by
Kyoto University Institute for Advanced Study (KUIAS), Kyoto Univ.
Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), RIKEN
MACS Program (MACS), Kyoto Univ.

In this seminar, I give an introduction to topological band structures. Topological band structure is the fundamental idea to understand phenomena such as the quantum Hall effect, topological insulators, and topological superconductors. Although originally found in fermionic electron systems, topological band structure is essentially a single-particle property, and thus the same phenomenon can arise also in bosonic systems. In fact, topological band structure does not even need quantum mechanics; topological band structure can arise in classical waves inside a periodic medium, such as electromagnetic waves or classical mechanical waves. In this seminar, I first give a brief introduction to key concepts in topological band structures, such as Berry curvature, Chern number, bulk-edge correspondence, and ten-fold way classification of topological insulators. I then explain how topological band structure can arise in classical systems, giving a brief introduction to the field of topological photonics and topological mechanics.

If you plan to attend the workshop, please register by July 13.

Hosted by Data Assimilation Research Team, RIKEN and Graduate School of Science, Kyoto University
Co-hosted by iTHEMS, RIKEN

iTHEMS-CEMS Joint Colloquium.

Professor Leggett is widely recognized as a world leader in the theory of low-temperature physics, and his pioneering work on superfluidity was recognized by the 2003 Nobel Prize in Physics.

Abstract:
One of the most surprising aspects of quantum mechanics is that under certain circumstances it does not allow individual physical systems, even when isolated, to possess properties in their own right. This feature, first clearly appreciated by John Bell in 1964, has over the last half-century been tested experimentally and found (in most people's opinion) to be spectacularly confirmed. More recently it has been realized that it permits various operations which are classically impossible, such as "teleportation" and secure-in-principle cryptography.
This talk is a very basic introduction to the subject, which requires only elementary quantum mechanics.

This seminar is aimed at scientists in general, not only to mathematicians.

10:00-10:45
Title: Multiple zeta functions associated with 2-colored rooted trees
Speaker: Dr. Masataka Ono (Keio University)
Abstract: In our recent work, we introduced a combinatorial object and finite sum associated with them which we call finite multiple zeta values associated with 2-colored rooted trees and gave a unified interpretation to some types of finite multiple zeta values. In this talk, we introduce multiple zeta function associated with 2-colored rooted tree and discuss its analytic properties, for example, the possible singularities and functional equations.

10:55-11:40
Title: Modular forms and trace formulas with applications to equidistributions of their Fourier coefficients
Speaker: Dr. Shingo Sugiyama (Nihon University)
Abstract: Modular forms are interesting objects in number theory as they are related to arithmetic problems. Trace formulas of Hecke operators acting on modular forms are very useful tools to study arithmetic invariants: Fourier coefficients, special values of L-functions, Hurwitz class numbers. We will start fundamental notions on modular forms and trace formulas of Hecke operators for non-experts, and introduce our results on a generalization of Serre’s vertical Sato-Tate law. Some results in this talk are based on a joint work with Masao Tsuzuki (Sophia University).

11:50-12:35
Title: On a generalization of Dobinski's formula
Speaker: Yoshinosuke Hirakawa (Keio University)
Abstract: Dobinski's formula is a very classical formula, which expresses the Bell number as an infinite series. Here, the Bell number is the number of partitions of a finite set. Such a "combinatorial-analytic" formula should lead us to more beautiful number theory. In this talk, we introduce a generalization of Dobinski's formula by means of a certain multiple generalization of the exponential function.

The International Symposium on Quantum Fluids and Solids (QFS) will be held at Ito International Research Center (IIRC) on Hongo campus of the University of Tokyo, Japan, from July 25 through 31, 2018. One of the sponsors of this conference is iTHEMS.

The QFS series started forty-three years ago making it one of the oldest series of international conferences in the field of low temperature physics. It has historically been focusing on physics of liquid and solid helium and hydrogen. But in this century its scope is expanding widely from laser cooled cold atoms to topological matters. At QFS2018 in Tokyo, this trend will be continued and with even more interdisciplinary aspects emphasized between the traditional subjects and those in broader physical systems.