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电子赌城官方大厅“博约学术论坛”系列报告-第284期

来源:    发布日期:2021年05月10日




­电子赌城官方大厅博约学术论坛系列报告

284

题目Response of a strongly interacting spin-orbit coupling system to a Zeeman field : Topological quantum spin liquid or not?

报告人:叶锦 教授美国密西西比州立大学

           时 间:2021511() 14:00-16:00

点:中心教学楼620

摘要:

Recently, there are flurries of theoretical and experimental researches to investigate the response of so called Kitaev materials to a Zeeman field. The most inspiring and provocative experiment is by Y. Kasahara, {\sl et.al}, Y. Matsuda, entitled " Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquid, Nature 559, 227-231 (2018)." In this work, starting from general symmetry principle, we construct various effective actions to study the response to a longitudinal Zeeman field of a strongly interacting spinor atom with a 2 dimensional (2d) anisotropic Rashba type of spin orbital coupling (SOC) in a square lattice. We find the interplay between the Zeeman field and the SOC leads to rich and novel classes of quantum commensurate (C-) and in-commensurate (IC-) phases, exotic excitations and novel quantum phase transitions (QPT). These phases include the collinear gapped Z-x at low Zeeman field, collinear gapped Z-FM at high Zeeman field, gapless co-planar canted phase at low SOC and gapless non-coplanar IC-Skyrmion crystal (IC-SkX) at large SOC in intermediate Zeeman fields. We also discover several novel classes of quantum phase transitions with dynamic exponents $ z=1, z=2 $ and anisotropic ones $ (z_x=3/2, z_y=3) $ respectively. We argue that it is the exotic form of the gapless excitations in the canted or IC-SkX phase which leads to the un-quantized thermal Hall conductivities even at zero temperature limit.

We give critical discussions on SOC materials such as Chiral magnets MnSi, Fe$_{0.5}$Co$_{0.5}$Si, especially 4d Kitaev materials $\alpha$-RuCl$_3$ in a Zeeman field.

简历

叶锦武教授是美国耶鲁大学理论物理博士。现在是美国密西西比州立大学教授。叶教授主要研究领域是强相互作用的电子玻色子自旋光子等的合作现象和量子或拓扑相变理论他的研究还涉及超对称性破缺共形场论和各种量子或拓扑相的量子引力对偶。He is currently visiting TD Lee institute in Shanghai. His two most recent research directions are on

(1) Topological Phases,topological phase transitions driven by interactions in various spin-orbit coupled systems.

(2) Quantum chaos and quantum information scramblings in cavity QED systems or in Sachdev-Ye-Kitaev (SYK) models. Connections between SYK models, conformal field theory and topological phases.

联系方式yangfan _blg@bit.edu.cn

邀请人:杨帆 教授

址:http:/

承办单位:物理学院先进光电量子结构设计与测量教育部重点实验室