Front propagation in random media: From extremal to activated dynamics

Abstract

Front propagation in a random environment is studied close to the depinning threshold. At zero temperature we show that the depinning force distribution exhibits a universal behavior. This property is used to estimate the velocity of the front at very low temperature. We obtain a Arrhenius behavior with a prefactor depending on the temperature as a power law. These results are supported by numerical simulations.Comment: 6 pages, 2 figures, accepted in Int. J. Mod. Phys.