ANDERSON LOCALIZATION IN ATOMIC MIXTURES

A mixture of two types of fermions with different mass in an optical lattice is considered. The light fermions are subject to thermal and quantum fluctuations, the heavy fermions only to thermal fluctuations. We derive the distribution of heavy fermions and study numerically the localization length of the light fermions in a two-dimensional lattice. Depending on the temperature of the system, a transition from extended states at low temperatures to localized states at high temperatures is found.