Abstract

Elastic interfaces driven in a disordered medium exhibit a phenomenon called avalanches: periods of rapid movement in between states where the interface is pinned. Today it is understood that the minimal ingredients to describe these systems are an elastic energy competing with the disorder energy, and a confining potential. When the center $w$ of this confining potential is slowly increased, one reaches the zero-temperature depinning transition, where physics becomes universal. One can measure correlations of the interface’s center-of-mass position as a function of $w$, which depends on the driving velocity. Its zero-velocity limit, $Delta(w)$, is the principle observable in the field-theory approach to disordered systems.

In this talk, I will first give an overview of the theory of disordered systems and the important concepts from its field theory. I will then discuss the field theory force-force correlator $\Delta(w)$, how it can be measured in experiment and what can be learned from it.