JOSEPHSON-JUNCTION LADDERS - GROUND-STATE AND RELAXATION PHENOMENA

This paper considers a Josephson junction array with the geometry of a ladder and anisotropy in the Josephson couplings. The ground-state pr oblem for the ladder corresponds to the one-for the one-dimensional ch iral XY model in a twofold anisotropy field, which allows for a rigoro us characterization of the ground-state phase diagram and the relevant elementary excitations for the system. The approach to equilibrium, w hich we study using Langevin dynamics, shows slow relaxation, typical of systems whose energy landscape in the configuration, space consists of a wealth of metastable states, dynamically disconnected.