报告时间：2021年7月5日（周一）上午10:30 - 11:30

报告地点：仲英楼B243

报告人：杨哲森（中国科学院大学卡弗里理论科学研究所）

报告摘要：

Topological nodal line semimetals can host stable chained, linked, or knotted line degeneracies in momentum space protected by symmetries. In this talk, I will show how to use the Jones polynomial (which is a knot invariant) to classify these semimetals. I will also show that every possible change in Jones polynomial is attributed to the local evolutions around every point where two nodal lines touch. As an application of our theory, I will illustrate that nodal chain semimetals with four touching points can evolve to a Hopf link. Finally, I will extend our theory to 3D non-Hermitian exceptional line semimetals.

Reference: Phys. Rev. Lett. 124, 186402 (2020)（Editors’ Suggestion）

报告人简介：杨哲森，2020年在中科院物理所获得博士学位，现于中国科学院大学卡弗里理论科学研究所从事博士后研究。主要研究方向是非厄米量子系统的新奇物理性质和拓扑能带理论。目前发表论文十余篇，其中包括6篇PRL。

邀请人：朱小宇