Elastic Scattering Time of Matter Waves in Disordered Potentials

Abstract

We report on an extensive study of the elastic scattering time τs 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 τs 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 kls ∼ 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. arXiv:1810.07574v4 [cond-mat.quant-gas]

Ultracold atoms in disordered potentials: elastic scattering time in the strong scattering regime

“…Using ultracold atoms propagating in optical disordered potentials, we experimentally and numerically determined in [43] the scattering time t s of a matter wave launched in a disordered potential ( ) V r with a welldefined momentum k i . By exploring a broad range of microscopic parameters, we collected an extensive set of data that we use all along this study as a support to explore the behavior of t s in the strong scattering regime.…”

“…By exploring a broad range of microscopic parameters, we collected an extensive set of data that we use all along this study as a support to explore the behavior of t s in the strong scattering regime. This section reviews the main results of [43], especially the comparison with the first order Born predictions, providing all the details relevant to the remainder of this work.…”

“…In a recent paper [43], we made an important step into that direction. There, the elastic scattering time of ultracold atoms in laser speckle disordered potential was directly measured over a very broad range of experimental parameters, and found to be in excellent agreement with numerical simulations.…”

“…The manuscript is organized as follows. In section 2, we review the measurements of the elastic scattering time and the comparison with the 1st order Born approximation as presented in Richard et al [43]. Section 3 provides the adequate framework, based on the direct connection between time properties and spectral functions, to further describe elastic scattering time beyond the first order Born approximation.…”

Dynamical observation of mobility edges in one-dimensional incommensurate optical lattices

“…More than 60 years ago, Anderson predicted and explained the well-known 'Anderson localization' in his landmark paper [1] which has been widely recognized as one of the significant phenomena in the condensed matter. In the years since, Anderson localization has found its way across a wide range of different topics, such as electronic systems [2], acoustic waves [3], quantum optics [4][5][6][7][8] and cold atomic gases [9][10][11][12][13][14][15][16]. A single-particle mobility edge as one of the most important concepts in a disordered system marks a critical energy E c separating localized from extended energy states and depends both on the disorder amplitudes and on the types of the disorder [17,18].…”