Phase diffusion as a model for coherent suppression of tunneling in the presence of noise - art. no. 016114

We study the stabilization of coherent suppression of tunneling in a driven double-well system subject to random periodic delta -function "kicks." We model dissipation due to this stochastic process as a phase diffusion proce ss for an effective two-level system, and derive a corresponding set of Blo ch equations with phase damping terms that agree with the periodically kick ed system at discrete times. We demonstrate that the ability of noise to lo calize the system on either side of the double-well potential arises from o verdamping of the phase of oscillation. and not from any cooperative effect between the noise and the driving field. The model is investigated with a square wave drive, which has qualitatively similar features to the widely s tudied cosinusoidal drive. but has the: additional advantage of allowing on e to derive exact analytic expressions.