Abstract
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. We also study the time evolution of the CBS peak and find it in 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.
- Received 19 July 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.195302
© 2012 American Physical Society
Viewpoint
Disorder Makes a Robust Matter-Wave Interferometer
Published 5 November 2012
Ultracold atoms can coherently scatter backwards from a disordered potential in a way similar to classical waves.
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