Diffusion in tilted periodic potentials: Enhancement, universality, and scaling.
An exact analytical expression for the effective diffusion coefficient of an overdamped Brownian particle in a tilted periodic potential is derived for arbitrary potentials and arbitrary strengths of the thermal noise. Near the critical tilt (threshold of deterministic running solutions) a scaling behavior for weak thermal noise is revealed and various universality classes are identified. In comparison with the bare (potential-free) thermal diffusion, the effective diffusion coefficient in a critically tilted periodic potential may be, in principle, arbitrarily enhanced. For a realistic experimental setup, an enhancement by 14 orders of magnitude is predicted so that thermal diffusion should be observable on a macroscopic scale at room temperature.
Reimann
P
P
Institut für Physik, Universität Augsburg, Universitätsstrasse 1, D-86135 Augsburg, Germany.
Van den Broeck
C
C
Linke
H
H
Hänggi
P
P
Rubi
J M
JM
Pérez-Madrid
A
A