  We consider a two-dimensional fully frustrated Josephson-junction array,
which is driven uniformly by oscillating currents. As the temperature is
lowered, there emerges a dynamic phase transition to an ordered state with
nonzero dynamic order parameter for small currents. The transition temperature
decreases monotonically with the driving amplitude, approaching zero at a
certain critical value of the amplitude. Above the critical value, the
disordered phase and the dynamically ordered phase are observed to appear
alternatively. The characteristic stochastic resonance behavior of the system
is also examined, which reveals that the resonance behavior of odd and even
harmonics can be different according to the zero-temperature state.
