Localization in periodically modulated speckle potentials

TL;DR

This paper investigates how periodic driving affects localization and transport in a 1D disordered quantum lattice with spatial correlations, revealing resonant hybridization, band homogenization, and signs of thermalization.

Contribution

It extends the understanding of Floquet states in correlated disordered systems by analyzing the effects of slow and strong driving on localization and spectral properties.

Findings

Resonant hybridization increases participation numbers in localized bands.

Strong driving homogenizes Floquet bands, causing states to become spatially smeared.

Signatures of thermalization are observed in the driven correlated disordered system.

Abstract

Disorder in a 1D quantum lattice induces Anderson localization of the eigenstates and drastically alters transport properties of the lattice. In the original Anderson model, the addition of a periodic driving increases, in a certain range of the driving's frequency and amplitude, localization length of the appearing Floquet eigenstates. We go beyond the uncorrelated disorder case and address the experimentally relevant situation when spatial correlations are present in the lattice potential. Their presence induces the creation of an effective mobility edge in the energy spectrum of the system. We find that a slow driving leads to resonant hybridization of the Floquet states, by increasing both the participation numbers and effective widths of the states in the strongly localized band and decreasing values of these characteristics for the states in the quasi-extended band. Strong driving homogenizes the bands, so that the Floquet states loose compactness and tend to be spatially smeared. In the basis of the stationary Hamiltonian, these states retain localization in terms of participation number but become de-localized and spectrum-wide in term of their effective widths. Signatures of thermalization are also observed.