MEMORY EFFECTS ON THE QUANTUM DIFFUSION OF A PARTICLE IN A FLUCTUATING MEDIUM

We introduce a phenomenological Hamiltonian for a particle in a medium with sitediagonal and off-diagonal disorder. Without assuming the usual white noise expression for the correlation between fluctuating variables, we arrive at a master equation using second order perturbation theory. This expression is expanded in powers of the correlation time. The mean square displacement and velocity are discussed and corrections to the diffusion coefficient are given. © 1979 Springer-Verlag.