Density Correlations in Cold Atomic Gases: Atomic Speckles in the Presence of Disorder

TL;DR

This paper investigates how disorder influences density correlations and speckle patterns in expanding cold atomic gases, including Fermi gases and Bose-Einstein condensates, revealing the impact of randomness on density fluctuations.

Contribution

It provides a theoretical analysis of density-density correlations and speckle size in cold atomic gases expanding in weak disorder, extending understanding to both Fermi gases and Bose-Einstein condensates.

Findings

Disorder significantly alters density correlations in expanding gases.

Estimated size of speckle spots depends on disorder strength and atomic statistics.

Both Fermi and Bose gases exhibit characteristic speckle patterns influenced by disorder.

Abstract

The phenomenon of random intensity patterns, for waves propagating in the presence of disorder, is well known in optics and in mesoscopic physics. We study this phenomenon for cold atomic gases expanding, by a diffusion process, in a weak random potential. We show that the density-density correlation function of the expanding gas is strongly affected by disorder and we estimate the typical size of a speckle spot, i.e., a region of enhanced or depleted density. Both a Fermi gas and a Bose-Einstein condensate (in a mean field approach) are considered.