Coherent Backscattering of Ultracold Atoms

Fred Jendrzejewski (1) , Kilian Müller (1) , Jérémie Richard (1) , Aditya Date (1) , Thomas Plisson (1) , Philippe Bouyer (2) , Alain Aspect (1) , Vincent Josse (1)

1 Laboratoire Charles Fabry / Optique atomique
2 lp2n-02,lp2n-11

We report on the direct observation of coherent backscattering (CBS) of ultracold atoms, in a quasi-two-dimensional configuration. Launching atoms with a well-defined momentum in a laser speckle disordered potential, we follow the progressive build up of the momentum scattering pattern, consisting of a ring associated with multiple elastic scattering, and the CBS peak in the backward direction. Monitoring the depletion of the initial momentum component and the formation of the angular ring profile allows us to determine microscopic transport quantities. The time resolved evolution of the CBS peak is studied and is found a fair agreement with predictions, at long times as well as at short times. The observation of CBS can be considered a direct signature of coherence in quantum transport of particles in disordered media. It is responsible for the so called weak localization phenomenon, which is the precursor of Anderson localization.

Keywords: Matter waves; Ultracold gases; trapped gases; Quantum transport; Wave propagation in random media; Localization effects (Anderson or weak localization)

Domains: Quantum Gases [cond-mat.quant-gas]; Atomic Physics [physics.atom-ph]; Disordered Systems and Neural Networks [cond-mat.dis-nn]

Fred Jendrzejewski, Kilian Müller, Jérémie Richard, Aditya Date, Thomas Plisson, et al.. Coherent Backscattering of Ultracold Atoms. Physical Review Letters, 2012, 109, pp.195302. ⟨10.1103/PhysRevLett.109.195302⟩. ⟨hal-00719458v4⟩