报告题目：Quantum geometric effects in multi-orbital superconductors

报告人：黄文副研究员  南方科技大学

报告时间：2023年5月31日（周三）14:00

报告地点：理六栋302会议室         邀请人：周涛、李铭

报告内容：

The Bloch electrons in multi-orbital or multiband systems are not featureless particles. Instead, they generally possess quantum geometric information characteristic of their wavevector-dependent orbital composition. This property manifests in the electromagnetic responses, in the sense that the transport properties of the multiple Bloch electrons at the same wavevector are quantum mechanically interwoven by interband velocities --- quantities that are related to the non-Abelian Berry connection among those states. One part of the quantum geometry, the Berry curvature, has been discussed widely in the context of topological band theories. However, the other part, the quantum metric, which is actually more universally present in multiband systems, has received far less attention. Recently, it was realized that quantum metric is crucial for the existence of flatband superconductivity. This talk will focus on several more novel effects enabled by quantum geometry (mostly quantum metric) in multiband superconductors. We will discuss: A) how quantum geometry induces intrinsic optical anomaly and how this may be related to the anomalous high-frequency spectral change  observed in some cuprate and iron-based superconductors; and B) how quantum geometry may facilitate the formation of pair-density-wave states.

专家简介：

黄文，现南方科技大学量子科学与工程研究院副研究员。2009年本科毕业于华南理工大学，2011年于加拿大Simon Fraser大学获得实验凝聚态物理硕士学位，2016年获得加拿大McMaster大学理论凝聚态物理学博士学位，2016年至2019年在清华大学高等研究院从事博士后研究(杨振宁青年学者)，2019年加入南方科技大学量子研究院至今。本研究小组主要研究方向为非常规超导电性，拓扑量子物态以及量子多体系统。