报告题目：

Entanglement diagnosis of many-body systems: applications to non-unitary conformal field theory and topological quantum field theories

多体系统纠缠诊断：在非幺正共形场论和拓扑量子场论中的应用

报告人：

poyao chang

报告时间：

2024年12月23日14:30

地点：

线上报告

#腾讯会议：248-217-557

https://meeting.tencent.com/dm/cWY20IBYLgVq

报告简介:

Entanglement measures provide powerful tools for diagnosing quantum many-body phases of matter. In particular, in (1+1)-dimensional systems with conformal symmetry, entanglement entropy exhibits logarithmic scaling, where the coefficient determines the central charge of the underlying conformal field theory (CFT). However, in the absence of the unitary condition, the central charge can be negative, leading to negative entanglement entropy. To address this issue, we propose the generalized entanglement entropy to extract the negative central charges in several examples. In addition, in (2+1)-dimensional systems described by topological quantum field theories (TQFT), the sub-leading term of the entanglement entropy is referred to as the topological entanglement entropy (TEE), which contains information about the topological data of the quasiparticles. In this talk, I would like to discuss the TEE for different bipartitions.

纠缠度量为诊断量子多体物质相提供了强大的工具。特别地，在具有共形对称性的(1+1)维系统中，纠缠熵呈现出对数缩放特性，其中的系数决定了底层共形场论的中心荷。然而，在非幺正条件下，中心荷可能为负，导致纠缠熵也为负值。为解决这一问题，我们提出了广义纠缠熵，以在多个实例中提取负中心荷。

另外，在由拓扑量子场论描述的(2+1)维系统中，纠缠熵的次主导项被称为拓扑纠缠熵（TEE），该术语包含了有关准粒子拓扑数据的信息。在这次演讲中，我希望讨论不同二分方式下的拓扑纠缠熵。

报告专家简介：

Associate Professor, Department of Physics, National Tsing Hua University. My main research focus is bridging different subfields in physics, including topological phenomena, quantum entanglement, strong correlations, and non-equilibrium physics. Previously, we have found a new type of strongly correlated topological insulators in heavy fermion systems. We also develop a new method to characterize the topological properties of non-equilibrium states. The topological properties are related to the quantum entanglement of these non-equilibrium state and open a possibility of engineering topological phases of matter. In addition, we are developing new concepts on understating the quantum chaos and many-body localization from the entanglement aspect.

国立清华大学物理系副教授。我的主要研究重点在于连接物理学的不同分支，包括拓扑现象、量子纠缠、强关联效应及非平衡物理。过去，我们在重费米子系统中发现了一种新型的强关联拓扑绝缘体。我们也开发了一种新方法来描述非平衡状态的拓扑特性。这些拓扑特性与这些非平衡状态的量子纠缠有关，并开启了通过设计实现物质拓扑相的可能性。另外，我们正从纠缠的角度出发，发展新的概念来理解量子混沌和多体局域化。这包括探索如何利用量子纠缠的视角来解析复杂系统中的混沌行为以及多体系统在受到强烈扰动时的定位现象。

欢迎各位老师同学参加！