报告题目: Many-body localization and quantum many-body scars: The strong and weak form of ergodicity breaking
报告时间: 2023年04月07日 周五 上午10:00-11:00
报告地点: 物理系理科楼 B315
报告摘要: The fate of an isolated quantum many-body system has attracted much attention in the past decade. One of the most important issues is whether such a system can reach thermalization under its own dynamics after a sudden quench. While thermalization is indeed expected in many cases, the opposite can happen in several different scenarios. In this talk, I will discuss our work in two systems that are known to escape thermalization. The first one is many-body localization, which is realized when strong quenched disorder is present. In this work, we studied many-body localization (MBL) for interacting one-dimensional lattice fermions in random (Anderson) and quasiperiodic (Aubry-Andre) models, focusing on the role of interaction range. We find an extremely rich phase diagram that reflects the crucial role of interaction range plays in the many-body localization transition [1-2]. The other is quantum many-body scar states, which is realized in a translationally invariant system. We find an interesting competition between scar states and random disorders. These results will help us better understand non-equilibrium phases of matter in a closed quantum many-body system.
References: D. Vu, K. Huang, X. Li, and S. Das Sarma, Phys. Rev. Lett. 128, 146601 (2022). K. Huang, D. Vu, X. Li, and S. Das Sarma, Phys. Rev. B 107, 035129 (2023).  K. Huang, Y. Wang, and X. Li, Phys. Rev. B 104, 214305 (2021).
报告人简介：Prof. Xiao Li is currently an Assistant Professor in the Department of Physics, City University of Hong Kong. He received his BSc degree from Peking University in 2008, and his Ph.D. degree in Physics from the University of Texas at Austin in 2014. Between 2015 and 2018 he worked as a postdoc associate in the Condensed Matter Theory Center, University of Maryland (College Park).
Prof. Xiao Li is mainly interested in novel states of matter that arise due to the interplay between topology, disorder, and electron-electron interactions. Recently his research focus mainly lies in various aspects of non-equilibrium systems such as many-body localization and quantum many-body scar states.