This question has also been investigated in three-dimensional disordered optical lattices. Recently, we have numerically computed the precise position of the mobility edge of atoms exposed to a continuous speckle potential and have studied its dependence versus the disorder strength and correlation function, thus providing a guide for future experiments. Furthermore, the position of the mobility edge has nothing in common with the one that could be expected for usual Gaussian or uncorrelated random potentials. These peculiar properties imply a large asymmetry in the position of the mobility edge and in the shape of spectral functions for blue and red speckle potentials. The resulting random potential is a speckle, whose statistics is characterized by an asymmetric (exponential) distribution and a non-vanishing correlation length. In many experiments, cold atomic gases are exposed to a laser light that has been transmitted or reflected through a diffusive plate. Recently, this problem has been the subject of intensive experimental activity aiming to precisely measure the position of the mobility edge, which separates the metallic from the insulating regime in the Anderson transition. The team is mainly interested in the behavior of cold atoms in the presence of optical random potentials, in particular in the regime where Anderson localization occurs (see also our recent results on dynamical localization).
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