报告题目：Linear level repulsion near exceptional points of non-Hermitian random matrices

报告人：汪晨 副教授

报告时间：2022年4月15日（星期五）15：30 - 17：00

报告地点：在线报告（腾讯会议ID：614 767 077）

报告摘要：

Level statistics are powerful tools for investigating complex quantum systems that random matrices could effectively describe. For example, the nearest-neighbor level-spacing distributions are one fundamental quantity for disordered systems and universal in many cases. It is well established that extended and localized states of Hermitian disordered systems follow the Wigner-Dyson distributions and the Poisson distribution in the thermodynamic limit, respectively, while the Ginibre distributions describe non-Hermitian disordered systems. However, the level statistics of non-Hermitian random matrices are not comprehensively studied, e.g., the level-spacing distribution of systems of neither Hermitian nor non-Hermitian with complete complex eigenvalues is still unknown. In this talk, I will show a new class of universal level statistics in the vicinity of exceptional points of non-Hermitian random matrices. Surprisingly, the nearest-neighbor level-spacing distributions show a universal linear level repulsion, in contrast to the cubic level repulsion of the Ginibre ensembles. Furthermore, a simple surmise can describe the level-spacing distributions in the thermodynamic limit. Cavity-magnon-polaritons are feasible platforms for observing the linear level repulsion at exceptional points, whose effective Hamiltonians are non-Hermitian due to the inevitable loss.

报告人简介：

Dr. Chen WANG received his Ph.D. degree from Hong Kong University of Science and Technology in 2016 and have joined the department of science of Tianjin University in 2019. His research interests include quantum phase transitions induced by disorders, topological phases, spintronics, and quantum chaos. Recently, he has focused on exploring novel phenomena in non-Hermitian systems.