Non-linear Hall response in Bloch oscillations with ultracold atoms

We propose that the non-linear Hall response with the preserved time-reversal symmetry can be observed in the Bloch oscillation of the ultracold atoms in optical lattices. In the short-time limit of Bloch oscillations with a DC driving field, the non-linear Hall current dominates with time reversal symmetry and is a second-order response of the external field strength. The associated Berry curvature dipole, which is the second order nonlinear coefficient of the driving field, can be extracted from the dynamics. In the presence of an AC driving field, the nonlinear Hall response will double the driving frequency in the case of time reversal symmetry.