报告题目:Symmetry-protected topological exceptional chains

主讲嘉宾：崔晓晗，香港科技大学博士后

报告时间：5月19日10：00-11：00

报告地点：致腾楼811

主持人：汪能 助理教授

报告简介:

In non-Hermitian systems, the band degeneracies (exceptional points) can form 1D exceptional lines (ELs) in 3D momentum space in the absence of any symmetries. In this talk, I will introduce a topological invariant associated with the winding of the complex eigenvalues around ELs and show that orientations can be assigned to theELs based on the sign of the invariants. Under the protection of the Mirror-adjoint symmetry, which is a non-Hermitian generalization of the Mirror symmetry, the ELs can join at a junction and form exceptional chains. We further design non-Hermitian photonic crystal structures and demonstrate that the exceptional chains can be readily observed in photonic systems.

报告人简介：崔晓晗，2014年进入香港科技大学物理系师从陈子亭教授攻读博士课程，并于2019年获得博士学位，现为香港科技大学物理系博士后。主要研究领域为光子晶体，非厄密系统以及拓扑物理。