Diffusive density profiles in a cold-atom expansion experiment

Abstract

In a recent experiment [McGehee et al., Phys. Rev. Lett. 111, 145303 (2013)], the expansion of non-interacting ultracold fermions was studied in a random speckle potential, and the observed density profiles were interpreted based on 3D Anderson localization. The purpose of this note is to demonstrate that slow diffusion of particles with a broad energy distribution and an energy-dependent diffusion coefficient leads to density profiles that agree with the measured data, but not with the behavior expected for 3D Anderson localization.

1 page. Comment on arXiv:1307.7175; v2: minor changes to final, published version

References in corpus (2)

• Cold atoms in the presence of disorder
• Three-Dimensional Anderson Localization in Variable Scale Disorder

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• A self-consistent theory of localization in nonlinear random media
• What can we learn from diffusion about Anderson localization of a degenerate Fermi gas?
• Stabilizing an ultracold Fermi gas against Fermi acceleration to superdiffusion through localization