Topological phases of matter exhibit remarkable electronic properties that offer unique possibilities for applications. A prominent example is the robust quantization of the Hall conductivity in quantum Hall insulators. A widespread technique for generating topological band structures in synthetic systems, such as ultracold atoms in optical lattices, is Floquet engineering. This method relies on the periodic modulation of the system’s parameters to emulate the properties of a non-trivial static system and facilitated the realization of paradigmatic topological lattice models including the famous Haldane model.

The rich properties of Floquet systems, however, transcend those of their static counterparts. The associated quasienergy spectrum can exhibit a non-trivial winding number, which leads to the appearance of anomalous chiral edge modes even in situations where the bulk bands have zero Chern numbers, hence, altering the well-known bulk-edge correspondence. A full classification of Floquet phases requires a new set of topological invariants. We have studied the rich Floquet phase diagram of a periodically-modulated honeycomb lattice using bosonic atoms. The novel properties of anomalous Floquet phases mentioned above open the door to exciting new non-equilibrium phases without any static analogue.

Link to join: http://s.ic.fo/MonikaAidelsburger11062020

L4G Seminar, June 11, 2020, 12:00. Online

Hosted by Prof. Maciej Lewenstein