The anomalous Floquet Anderson insulator in a continuously driven optical lattice

TL;DR

This paper demonstrates that a continuously driven optical lattice can host a stable anomalous Floquet Anderson insulator phase, with localized bulk states and quantized pumped charge, extending the understanding of Floquet topological phases.

Contribution

It shows the stability of the AFAI phase under continuous driving protocols in a realistic experimental setup with disorder.

Findings

Disorder induces localization of bulk states in the AFAI.

Quantized pumped charge persists despite disorder.

AFAI phase exists over a range of disorder strengths.

Abstract

The anomalous Floquet Anderson insulator (AFAI) has been theoretically predicted in step-wise periodically driven models, but its stability under more general driving protocols hasn't been determined. We show that adding disorder to the anomalous Floquet topological insulator realized with a continuous driving protocol in the experiment by K. Wintersperger et. al., Nat. Phys. $\textbf{16}$, 1058 (2020), supports an AFAI phase, where, for a range of disorder strengths, all the time averaged bulk states become localized, while the pumped charge in a Laughlin pump setup remains quantized.