慕尼黑工业大学

摘要：

Conventional phases and their phase transitions are characterized by local order parameters. However, intrinsic topological phases of matter do not have local order parameters, making their topological phase transitions particularly challenging to understand. To search for order parameters for topological phase transitions, we focus on two classes of systems: i) Frustration-free models, whose ground states can be exactly expressed as projected entangled pair states (PEPS); ii) Generic models, whose ground states lack analytical expression and are challenging to calculate numerically. For frustration-free models, we construct order parameters using non-invertible matrix product operators (MPOs) acting on the entanglement degrees of freedom of the PEPS. For generic models, we establish order parameters using the emergent higher-form symmetry on physical degrees of freedom, and this order parameter can be used to experimentally probe topological phase transitions. Our work demonstrates that order parameters for topological phase transitions can be constructed using generalized symmetries.

报告人简介：

徐文涛博士，本科就读于西安交通大学应用物理专业, 2015年7月获得学士学位。博士就读于清华大学物理系张广铭教授课题组，2020年8月获得博士学位。2020年10月到2022年10月在维也纳大学从事博士后研究工作，2022年10月至今在慕尼黑工业大学从事博士后研究工作。研究方向为量子多体物理，张量网络以及拓扑物态等，并在国际主流学术期刊发表多篇论文。

邀请人：廖海军（82649377）