It was found that the diffusion of a 2-dimensional array of particles, driven by a constant force in the presence of a periodic external potential, exhibited an hierarchy of dynamic phase transitions as the driving force was varied. This behavior could be explained in terms of a simple phenomenological approach which reduced the system of strongly interacting particles to one of weakly interacting quasi-particles (kinks). The richness of the strongly coupled system was retained in that, contrary to the case of a single Brownian particle, the array exhibited an hysteretic behavior; even at non-zero temperatures.

O.M.Braun, T.Dauxois, M.V.Paliy, M.Peyrard: Physical Review Letters, 1997, 78[7], 1295-8