Adiabatic realization of anomalous Floquet topological systems

In an international collaboration with Kyoto University, University of Hamburg and TU Berlin, we introduce a robust way to realize anomalous Floquet topological systems via adiabatic sweeps, thus connecting these topological systems to a two-dimensional generalization of Thouless charge pumps. Anomalous Floquet topology appears only in driven systems and breaks with the conventional bulk-boundary correspondence by providing chiral edge states even for topologically trivial bands. Usually one considers a drive at frequencies that are near-resonant with the system's bandwidth, where Floquet heating plays a significant role in interacting systems. In the new work, we show that anomalous Floquet topological phases can be realized in an adiabatic protocol, where the system is always in the instantaneous ground state and where Floquet heating is significantly suppressed. We realize the new concept in an experiment with ultracold rubidium atoms in a tunable hexagonal optical lattice and observe a robust response in the interacting system.
The preprint is available at Asteria et al.
