Expansion of matter waves in static and driven periodic potentials

TL;DR

This paper investigates the non-equilibrium expansion dynamics of cold atoms in optical lattices, revealing a two-phase expansion process and offering a method to measure tunneling rates from experimental data.

Contribution

It introduces a detailed analysis of atom cloud expansion in optical lattices, connecting theoretical modeling with experimental observations to extract tunneling parameters.

Findings

Initial quadratic expansion transitions to ballistic behavior

The model accurately describes recent experimental results

Provides a method to determine intersite tunneling from measurements

Abstract

We study the non-equilibrium dynamics of cold atoms held in an optical lattice potential. The expansion of an initially confined atom cloud occurs in two phases: an initial quadratic expansion followed by a ballistic behaviour at long times. Accounting for this gives a good description of recent experimental results, and provides a robust method to extract the effective intersite tunneling from time-of-flight measurements.