Abstract

It is shown that diffusion, in momentum space, exists for the periodically kicked quantum rotator when dynamic disorder is considered on the external potential upsilon (theta) (the amplitude of the kick). This is opposite to the behavior without disorder (deterministic) where localization exists. Explicitly if upsilon (theta) is stochastic, then the diffusion coefficient is linked to the second derivative of the correlation function (i-upsilon(theta + phi)e - i-upsilon(theta)> at phi = 0. Two examples are considered, the Gaussian process and the random linear case upsilon (theta) = eta-theta (with eta a random parameter). In both cases, the diffusion coefficient was evaluated exactly. Finally, we conjecture that this diffusive behavior may be found in a great variety of kicked systems with static disorder.