Can quantum fluctuation enhance diffusion in a corrugated plane?

Abstract

By means of the effective diffusion coefficient of a particle be determined by the envelope width of its spatial distribution, we study the influence of quantum fluctuation upon the diffusion of the particle in a corrugated plane. The model allows for a power-spectrum quantum noise and a biased periodic potential. A comprehensive method is developed, which includes three techniques: the fast Fourier transform is used to generate quantum colored noise, solving numerically the generalized Langevin equation by the Monte-Carlo method, and the quantum-averaging correction of nonlinear force is taken account into the calculation. The prominent result is demonstrated that the effective diffusion coefficient of the particle driven by quantum thermal noise is less than the classical one when the biased force arrives at its critical value, where the local minima of potential vanish just. Moreover, the time index of the position variance of a super-Ohmic damping particle varies with the biased force. This is due to a fact that the motion of particle exhibits mixing of the locked and running states in such potential, however, the quantum fluctuation increases mobility but decreases the probability of the particle in a locked state.