Wavepacket dynamics in topological Floquet bands

Floquet engineering, i.e., the periodic modulation of a system’s parameters, has proven as a powerful tool for the realization of quantum systems with exotic properties, which are otherwise not accessible in static realizations. We have engineered such systems on our experimental platform, which consists of bosonic atoms in a periodically driven optical honeycomb lattice. Depending on the driving parameters several topological phases can be realized, including genuine out-of-equilibrium topological phases without any static analogue [1].

As the bulk-boundary correspondence relates the properties of the bulk of a topological system to the number of topologically protected edge modes at the boundaries, we study the behavior in both regions. To this end, we investigate the real-space evolution of an initially-localized wavepacket after release from a tightly-focused optical tweezer in the vicinity of a hard-wall potential as well as in the bulk of this system.

[1] Wintersperger et al. Realization of an anomalous Floquet topological system with ultracold atoms. Nat. Phys. 16, 1058–1063 (2020).