Interactions and localization: two interacting particles approach
  It is shown that two repulsing / attracting particles in a random potential can propagate coherently on a distance much larger than one-particle localization length without interaction. In dimension $d$ this leads to delocalization of pairs formed by two repulsing / attracting particles. The results of numerical simulations allow to understand some specific features of this effect. 
D.L.Shepelyansky