报告题目：Probing geometric phases in cold atomic topological bands

报 告 人：Lih-King Lim (Zhejiang University)

报告时间：1月3日（周四）上午10:00-11:00

报告地点：致远楼213

报告邀请人：王钢

报告摘要：Thanks to recent progress in engineering topological band structures with cold atoms, the accessible parameter regime of artificial crystal extends beyond that of its solid-state counterpart. For example, the physics of 2D Dirac cones merging as well as the 2D topological Haldane model were realized with cold atoms in tunable optical lattices. Furthermore, cold atomic systems also open the door for probing interesting geometric quantities which are otherwise difficult to observe [1]. Specifically, we study the Landau-Zener processes in topological bands with Bloch-oscillations-type experiment, realizing a Stuckelberg interferometer. A new geometric phase shift is identified in the interference fringes [2]. If time permits, we shall discuss our recent work on the winding vector (rather than winding number) of Dirac points [3].

[1] T. Li et al, Science 352, 1094 (2016); Tarnowski et al, Phys. Rev. Lett. 118, 240403 (2017).

[2] L.-K. Lim, J.-N. Fuchs, and G. Montambaux, Phys. Rev. Lett. 112, 155302 (2014).

[3] G. Montambaux, et al, Phys. Rev. Lett. 121, 256402 (2018).

报告人简介： Lih-King Lim obtained his PhD (2010) in Theoretical Physics from Utrecht University, The Netherlands. He continued post-doctoral work (2010-2015) at LPS and Institut d'Optique, CNRS, Orsay, France, and Max Planck Institute PKS, Dresden, Germany. In 2015, he joined IAS Tsinghua University as an associate member (faculty). Since 2018, he is assistant professor at the Institute of Modern Physics, Department of Physics, Zhejiang University. His research interests are theoretical studies of macroscopic manifestation of topological/geometric effects in quantum materials, as realized in both cold atomic and condensed matter systems. He has work on theoretical studies of artificial gauge fields in cold atoms and its associated many-body effects, Landau-Zener transitions in Dirac cone systems, as well as pseudospin models for topological semimetals.