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Floquet Engineering in Quantum Systems

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


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. 

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