Phase Diffusion as a Model for Coherent Suppression of Tunneling in the Presence of Noise

John Grondalski
Optical Sciences and Engineering
University of New Mexico

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 process for an effective two-level system and derive a corresponding set of Bloch equations with phase damping terms that agree with the periodically kicked system at discrete times. We demonstrate that the ability of noise to localize the system on either side of the double-well potential arises from overdamping 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 studied cosinusoidal drive, but has the additional advantage of allowing one to derive exact analytic expressions.

12:00 p.m., Friday, August 25, 2000

Room 184, Physics and Astronomy Building

Northeast Corner of Lomas and Yale, Albuquerque, New Mexico