报告题目：Topological states: classification, detection and interaction with phonons

报告人：刘东皓博士

报告时间：2023年11月02日（周四）14:30

报告地点：理六栋320        邀请人：朱起忠

报告内容：

Quantum states, which can be accessed and manipulated with advanced technology, are of great interest in the current era. Among them, topological quantum matters exhibit rich phases and robust boundary states at mesoscopic or even macroscopic scales, making them attractive for both their theoretical elegance and their practical applications. In this talk, I will present my theoretical research on the Z-class topological insulators in odd dimensions. After a short review of the classification of noninteracting topological insulators/superconductors, I will explain the ambiguity of winding numbers, which differ from the familiar Chern numbers. I will also demonstrate the equivalence of Z-class topological insulators by constructing models in odd dimensions. Next, I will introduce a way to detect the edge states of one-dimensional topological superconductors using dissipative interactions. The dissipative tunneling can be mapped to a Coulomb gas model, which can be solved using renormalization group. The interaction-induced renormalization will lead to distinct universal zero-bias conductance behaviors for different types of Andreev reflections, characterized by different power laws in temperature. At the end, I will discuss the exotic phonon behaviors in topological materials such as Weyl semimetals: when phonons interact with electrons in special states, they will exhibit phonon dynamics that deviate from the conventional way, leading to novel phenomena such as phonon circular dichroism.

专家简介：

刘东皓博士于2013年在山东大学物理学院获得学士学位，之后在北京大学量子材料中心施均仁教授的指导下从事凝聚态物理理论研究并于2018年获得博士学位。此后他分别在清华大学刘东副教授研究组（2018年-2021年）以及以色列的巴伊兰大学Dmitri Gutman教授研究组（2021年-现在）做博士后研究。其主要的研究方向为拓扑量子物态，介观量子输运，声子动力学等。