Reversible to Irreversible Flow Transition in Periodically Driven   Vortices
  We show that periodically driven superconducting vortices in the presence of quenched disorder exhibit a transition from reversible to irreversible flow under increasing vortex density or cycle period. This type of behavior has recently been observed for periodically sheared colloidal suspensions and we demonstrate that driven vortex systems exhibit remarkably similar behavior. We also provide evidence that the onset of irreversible behavior is a dynamical phase transition. 
N. Mangan, C. Reichhardt, and C.J. Olson Reichhardt