报告题目：Generalizations of some familiar quantities and concepts to non-Hermitian systems

报告人：史哲雨 研究员（华东师范大学）

报告时间：2023年5月8日（周一）上午11:10

报告地点：光电所二层报告厅

报告摘要：  

I will discuss two of our recent works on non-Hermitian physics of open systems that lead to generalizations of some familiar physical quantities and concepts to non-Hermitian systems.

In the first part, I will discuss the problem of how to characterize a short-range inelastic collision in ultracold atomic gases. I will show that the short-range two-body loss can be described by a complex s-wave scattering length which may be tuned by optical Feshbach resonances. We give different methods to regularize or renormalize this loss term in a Lindblad master equation. As an example, we apply our model to investigate the influence of two-body loss on the dynamics of Bose-Einstein condensate and three-body Efimov physics.

In the second part, I will discuss the singularities of density of states in non-Hermitian bands. These singularities are known as Van Hove singularities in conventional Hermitian band theory. I will show that the complex energy spectrums of non-Hermitian band structures can lead to more complicated and interesting types of singularities as compared to their Hermitian counterparts.

报告人简介：  

史哲雨博士毕业于清华大学高等研究员，现担任华东师范大学精密光谱科学与技术国家重点实验室研究员。史哲雨研究员的研究兴集中在冷原子气体的理论方面，包括冷原子气体中的少体物理，开放体系的非厄米物理物理，冷原子气体中的多体动力学问题等。