Coherent backscattering of Bose-Einstein condensates in two-dimensional disorder potentials

TL;DR

This paper investigates how weak interactions in a Bose-Einstein condensate affect coherent backscattering in a 2D disordered potential, revealing a transition from constructive to destructive interference.

Contribution

It demonstrates the impact of atom-atom interactions on coherent backscattering, combining numerical Gross-Pitaevskii simulations with a diagrammatic weak localization theory.

Findings

Sharp backscattering cone in non-interacting case

Transition to a backscattering dip with weak interactions

Agreement between numerical and theoretical results

Abstract

We study quantum transport of an interacting Bose-Einstein condensate in a two-dimensional disorder potential. In the limit of vanishing atom-atom interaction, a sharp cone in the angle-resolved density of the scattered matter wave is observed, arising from constructive interference between amplitudes propagating along reversed scattering paths. Weak interaction transforms this coherent backscattering peak into a pronounced dip, indicating destructive instead of constructive interference. We reproduce this result, obtained from the numerical integration of the Gross-Pitaevskii equation, by a diagrammatic theory of weak localization in presence of a nonlinearity.