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

Abstract

We study the elastic scattering time t s of ultracold atoms propagating in optical disordered potentials in the strong scattering regime, going beyond the recent work of Richard et al (2019 Phys. Rev. Lett. 122 100403). There, we identified the crossover between the weak and the strong scattering regimes by comparing direct measurements and numerical simulations to the first order Born approximation. Here we focus specifically on the strong scattering regime, where the first order Born approximation is not valid anymore and the scattering time is strongly influenced by the nature of the disorder. To interpret our observations, we connect the scattering time t s to the profiles of the spectral functions that we estimate using higher order Born perturbation theory or self-consistent Born approximation. The comparison reveals that self-consistent methods are well suited to describe t s for Gaussiandistributed disorder, but fails for laser speckle disorder. For the latter, we show that the peculiar profiles of the spectral functions, as measured independently in Volchkov et al (2018 Phys. Rev. Lett. 120 060404), must be taken into account. Altogether our study characterizes the validity range of usual theoretical methods to predict the elastic scattering time of matter waves, which is essential for future close comparison between theory and experiments, for instance regarding the ongoing studies on Anderson localization. s OPEN ACCESS RECEIVED

Bichromatic state-dependent disordered potential for Anderson localization of ultracold atoms

“…The function can then be expressed as a function of the autocorrelation function of the complex amplitude (calculated in Sect. 1 of Appendix A) as This correlation function is central to quantum transport studies as it directly translates into the spatial frequency distribution of the potential that governs the scattering properties of the atoms [ 9 , 36 , 38 – 40 ]. A full calculation is presented in section A.3 of Appendix A, and here, we only discuss some of its most important features in the transverse and longitudinal directions.…”

Numerical investigation of localization in two-dimensional quasiperiodic mosaic lattice

“…It is known that electrons in lower dimensions are more prone to localization in the presence of even weak disorder [2,3,5,6]. Theoretical progresses [7][8][9][10][11][12] and experimental realizations [13][14][15][16][17] of the delocalization-localization transition (or the * Author to whom any correspondence should be addressed. metal-insulator transition, MIT) in disordered materials are still exciting topics until today.…”

Numerical Investigation of Localization in Two-Dimensional Quasiperiodic Mosaic Lattice

“…It is known that electrons in lower dimensions are more prone to localization in the presence of even weak disorder [2,3,5,6]. Theoretical progresses [7][8][9][10][11][12] and experimental realizations [13][14][15][16][17] of the delocalization-localization transition (or the metal-insulator transition, MIT) in disordered materials are still exciting topics until today. On the other hand, quasiperiodicity is a delicate structure between order and disorder [18,19].…”