报告题目：Breaking chains by Hermiticity: Topological phases of matter in non-Hermitian systems

报告人：芮文彬博士 香港大学

报告时间：2023年12月19日（周二）10:00

报告地点：理六栋302会议室         邀请人：张丹伟

报告内容：

Like quantum mechanics, the formulation of the theory for topological phases of matter relies on the fundamental assumption of Hermiticity. In this talk, I will discuss non-Hermitian topological phases, an emerging research field that goes beyond the constraints of the Hermitian assumption. In these systems, the two key aspects of topological classification - symmetry and band structure - become more diverse and enjoy higher degrees of freedom, leading to a substantial enrichment of topological phases. By identifying a new kind of non-Hermitian spatial symmetry, we discover unique topological semimetals and uncover nonlocal Hermitian conjugate pairs of non-Hermitian band degeneracies, which result in a symmetry-enforced violation of the well-established Fermion doubling theorem in the long-time limit. Furthermore, we address the challenge of experimentally realizing the numerous theoretically predicted new phases, which are hindered by a fundamental symmetry barrier. Our proposed solution involves using gauge fields to overcome this barrier, paving the way for a broader realization of non-Hermitian topological phases.

专家简介：

芮文彬博士分别于2012年和2015年在南京大学获得本科和硕士学位，2019年于德国马克斯·普朗克固体物理研究所完成博士学位。目前在香港大学从事博士后研究，并在2022年获得香港研究资助局冠名博士后奖。主攻凝聚态物理理论，在Phys. Rev. Lett.、Phys. Rev. B、Phys. Rev. Research等期刊上发表论文16篇，其中以第一作者身份发表11篇，以通讯作者身份发表6篇。目前的研究重点为拓扑物态的基本理论，致力于发现新型物态、实现方案及量子应用。