Resonant directed diffusion in nonadiabatically driven systems

We show that a high-frequency field may resonantly decrease the activation energy of escape from a potential well. For systems in spatially periodic potentials, the effect is different for the transitions in opposite directions, which gives rise to resonantly directed diffusion (DD). DD arises in both asymmetric and symmetric periodic potentials. It depends exponentially strongly on the field magnitude, and its direction can be controlled by varying the field spectrum.