Phase Coherence and Nonequilibrium Behavior in Josephson Junction Arrays

We model a two-dimensional periodic array of Josephson junctions in a transverse magnetic field by the uniformly frustrated $\mathrm{XY}$ model. We report the results of extensive nonequilibrium simulations of the array within the resistively-shunted-junction model. $I-V$ curves are computed for the unfrustrated and fully frustrated cases, and consistency with recent experiments is found. For the fully frustrated case, new theoretical ideas are presented which show the Ising degrees of freedom to dominate nonequilibrium behavior near $T_c$.