Multidimensional and memory effects on diffusion of a particle - art. no. 061112

The diffusion of an overdamped Brownian particle in the two-dimensional (2D ) channel bounded periodically by a parabola is studied, where the particle is subject to an additive white or colored noise. The diffusion rate const ant D* of the particle is evaluated by the quasi-2D approximation and the e ffective potential approach, and the theoretical result is compared with th e Langevin simulation. The properties of the diffusion rate constant are st ressed for weak and strong noise cases. It is shown that, in an entropy cha nnel, the value of D* in units of Q decreases with increasing intensity of the colored noise. In the presence of energetic barriers, a nonmonotonic be havior of the reduced diffusion rate constant D*Q(-1) as a function of the noise intensity is shown.