Enhanced backscattering of a dilute Bose-Einstein condensate

TL;DR

This paper investigates the phenomenon of enhanced backscattering in a dilute Bose-Einstein condensate within a disordered optical potential, combining experimental observations with numerical simulations to analyze underlying effects.

Contribution

It provides the first combined experimental and numerical analysis of backscattering phenomena in a Bose-Einstein condensate in disordered potentials, highlighting multiple contributing effects.

Findings

Pronounced backscattering peak observed experimentally.

Numerical simulations reveal additional effects like backscattering echo.

Position-momentum correlations influence the backscattering enhancement.

Abstract

We study experimentally and numerically the quasi-bidimensional transport of a $^{87}$Rb Bose-Einstein condensate launched with a velocity $v_0$ inside a disordered optical potential created by a speckle pattern. A time-of-flight analysis reveals a pronounced enhanced density peak in the backscattering direction $-v_0$, a feature reminiscent of coherent backscattering. Detailed numerical simulations indicate however that other effects also contribute to this enhancement, including a "backscattering echo" due to the position-momentum correlations of the initial wave packet.