物理学院 School of Physics, Nanjing University

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Fractionalization and anomalies in two-dimensional topological phases

2017年12月28日

 

时间:2017年12月28日( 星期四)上午 10:00
地点:唐仲英楼 A313
报告人:程蒙 教授
单位:耶鲁大学物理系

摘要:
Topological phases of matter in two dimensions support fractionalized excitations. They exhibit a number of fascinating phenomena, such as anyonic exchange and braiding statistics and fractional quantum numbers, or symmetry fractionalization. A famous example is the fractionally charged quasiholes in quantum Hall systems while the electrons making up the system have charge one. In this talk I will discuss recent advances in the theory of symmetry fractionalization and global anomalies for 2D topological phases. I will describe how to systematically classify symmetry fractionalization in a topologically ordered phase, and how certain seemingly consistent patterns of symmetry fractionalization are in fact “anomalous”. This kind of anomaly is deeply connected to symmetry-protected topological phases in three dimensions via bulk-boundary correspondence. With these ideas, I will discuss a new perspective on the classic Lieb-Schultz-Mattis theorem and its higher-dimensional version by Oshikawa and Hastings, and possible refinements and generalizations.
 
报告人简介:程蒙教授长期从事凝聚态理论研究,主要关注拓扑超导体、量子自旋液体等体系中的拓扑量子相变及拓扑序等问题,在PRL、PRX、PRB等期刊发表论文20余篇。2008年在南京大学获得学士学位,2013年在马里兰大学获得博士学位,导师为Sankar Das Sarma,之后在Microsoft Station Q从事博士后研究。2017年7月起成为耶鲁大学物理系的助理教授。

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