Freezing, accelerating and slowing directed currents in real time with   superimposed driven lattices
  We provide a generic scheme offering real time control of directed particle transport in superimposed driven lattices. This scheme allows to accelerate, slow and freeze the transport on demand, by switching one of the lattices subsequently on and off. The underlying physical mechanism hinges on a systematic opening and closing of channels between transporting and non-transporting phase space structures upon switching, and exploits cantori structures which generate memory effects in the population of these structures. Our results should allow for real time control of cold thermal atomic ensembles in optical lattices, but might also be useful as a design principle for targeted delivery of molecules or colloids in optical devices. 
Aritra K. Mukhopadhyay, Benno Liebchen, Thomas Wulf and Peter   Schmelcher
nlin.CD cond-mat.other cond-mat.quant-gas physics.class-ph