Symmetries and transport in site-dependently driven quantum lattices

TL;DR

This paper develops a numerical method to analyze quantum particles in driven lattices, demonstrating control over Floquet spectrum crossings and particle currents through symmetry manipulation.

Contribution

It introduces a novel numerical scheme for Floquet mode analysis and shows how to manipulate spectral crossings and currents via symmetry adjustments.

Findings

Exact crossings can be turned into avoided crossings.

Avoided crossing widths are tunable by local driving parameters.

Asymptotic currents are controllable within certain parameter ranges.

Abstract

We explore the quantum dynamics of particles in a spatiotemporally driven lattice. A powerful numerical scheme is developed, which provides us with the Floquet modes and thus enables a stroboscopic propagation of arbitrary initial states. A detailed symmetry analysis represents the cornerstone for an intricate manipulation of the Floquet spectrum. Specifically, we show how exact crossings can be converted into avoided ones, while the width of these resulting avoided crossings can be engineered by adjusting parameters of the local driving. Asymptotic currents are shown to be controllable over a certain parameter range.