Speaker: 安钧鸿 兰州大学
Time: 2021-06-23 10:00-2021-06-23 11:30
Venue: S327, MMW Building

Abstract:

Floquet engineering, i.e., coherent control via periodic driving, has become a highly versatile tool in quantum control. The main idea resides in that the concept of energy spectrum in static systems can be completely inherited as the quasienergy spectrum in periodically driven systems according to Floquet theory. Many efforts have been devoted to explore non-trivial effects induced by periodic driving on quantum systems. In this talk, I will report that interesting nonequilibrium quantum phase transitions can be triggered by engineering non-trivial band-gap structure and bound states in the quasi-energy spectrum using periodic driving. I will clarify this idea by Floquet engineering to second-order topological semimetals (SOTSMs). Many exotic SOTSMs absent in natural materials, e.g., a widely tunable number of Dirac nodes and hinge Fermi arcs, the adjacent Dirac nodes with same chirality, and the coexisting Dirac nodal points and nodal loops, and hybrid-order Weyl semimetals with the coexisting hinge and surface Fermi arcs, are generated at ease by the periodic driving. By this, I want to deliver a message that Floquet engineering supplies a convenient way to explore exotic topological matters by adding time-periodicity as a novel control dimension to quantum systems. 

Short Bio:

安钧鸿，现任兰州大学物理科学与技术学院教授。2005年在兰州大学获博士学位，并留校工作。2006年至2007年在台湾成功大学从事博士后，2007年至2014年在新加坡国立大学从事研究员、访问研究员；2011年受聘为教授；2013年入选教育部新世纪优秀人才支持计划；2016年入选甘肃省飞天学者；2017年入选中央军委科技委国防科技创新特区主题专家组专家；2019年入选国家“万人计划”青年拔尖人才。主要从事开放量子系统、周期性驱动系统等非平衡量子物理问题研究。