Short-range depinning in the presence of velocity weakening.

Abstract

Phenomena including friction and earthquakes are complicated by the joint presence of disorder and nonlinear instabilities, such as those triggered by the presence of velocity weakening. In de Geus and Wyart [Phys. Rev. E 106, 065001 (2022)10.1103/PhysRevE.106.065001], we provided a theory for the nucleation of flow and the magnitude of hysteresis, building on recent results on disorder-free systems described by so-called rate-and-state descriptions of the frictional interface, and treating disorder perturbatively. This theory was tested for models of frictional interfaces, where long-range elastic interactions are present. Here we test it for short-range depinning, and confirm that (i) nucleation is triggered by avalanches, governed by a critical point at some threshold force f_{c} close to the minimum of the flow curve and that (ii) due to an armoring mechanism by which the elastic manifold displays very little plasticity after a big slip event, very slowly decaying finite size effects dominate the hysteresis magnitude, with an exponent we can relate to other observables.