Collective Transport in Disordered Systems

There is a growing interest in the study of complex systems, many of which are dissipative driven structures with disorder and competing interactions, and with many interacting degrees of freedom. In them, an externally applied force very slowly drives the system to an unstable state, where the onset of collective motion (i.e., an avalanche) occurs, releasing a sudden burst of kinetic energy which allows the system to move to another metastable configuration. The moveable objects (e.g., flux lines or grains in a sand dune) are slowly driven again and again toward unstable states, leading to further avalanches. We theoretically study collective transport phenomena and also collaborate with experimental groups studying driven complex disordered systems.