Controllable diffusion of cold atoms in a harmonically driven and tilted   optical lattice: Decoherence by spontaneous emission
  We have studied some transport properties of cold atoms in an accelerated optical lattice in the presence of decohering effects due to spontaneous emission. One new feature added is the effect of an external AC drive. As a result we obtain a tunable diffusion coefficient and it's nonlinear enhancement with increasing drive amplitude. We report an interesting maximum diffusion condition. 
Navinder Singh