Elastic Scattering Time of Matter-Waves in Disordered Potentials

TL;DR

This study comprehensively measures and analyzes the elastic scattering time of matter-waves in disordered optical potentials, revealing the influence of disorder statistics and challenging existing criteria in different disorder regimes.

Contribution

It provides the first extensive experimental and numerical analysis of scattering times across regimes, highlighting the impact of disorder statistics on scattering behavior.

Findings

The scattering time spans over three orders of magnitude.

Disorder statistics significantly affect the relevance of the Ioffe-Regel criterion.

Deviations from the criterion are observed for laser speckle disorders.

Abstract

We report on an extensive study of the elastic scattering time $\tauS$ of matter-waves in optical disordered potentials. Using direct experimental measurements, numerical simulations and comparison with first-order Born approximation based on the knowledge of the disorder properties, we explore the behavior of $\tauS$ over more than three orders of magnitude, spanning from the weak to the strong scattering regime. We study in detail the location of the crossover and, as a main result, we reveal the strong influence of the disorder statistics, especially on the relevance of the widely used Ioffe-Regel-like criterion $k\lS\sim 1$. While it is found to be relevant for Gaussian-distributed disordered potentials, we observe significant deviations for laser speckle disorders that are commonly used with ultracold atoms. Our results are crucial for connecting experimental investigation of complex transport phenomena, such as Anderson localization, to microscopic theories.