Force correlator for driven disordered systems at finite temperature.

Abstract

When driving a disordered elastic manifold through quenched disorder, the pinning forces exerted on the center of mass are fluctuating, with mean f_{c}=-F_{w}[over ¯] and variance Δ(w)=F_{w}F_{0}[over ¯]^{c}, where w is the externally imposed control parameter for the preferred position of the center of mass. Δ(w) was obtained via the functional renormalization group in the limit of vanishing temperature T→0, and vanishing driving velocity v→0. There are two fixed points, and deformations thereof, which are well understood: The depinning fixed point (T→0 before v→0) rounded at v>0, and the zero-temperature equilibrium fixed point (v→0 before T→0) rounded at T>0. Here we consider the whole parameter space of driving velocity v>0 and temperature T>0, and quantify numerically the crossover between these two fixed points.