Diffusion in the Mean for an Ergodic Schrödinger Equation Perturbed by a Fluctuating Potential

Diffusive scaling of position moments and a central limit theorem are obtained for the mean position of a quantum particle hopping on a cubic lattice and subject to a random potential consisting of a large static part and a small part that fluctuates stochastically in time. If the static random potential is strong enough to induce complete localization in the absence of time dependent noise, then the diffusion constant is shown to go to zero, proportional to the square of the strength of the time dependent part.