New Quantum Phase in a One-Dimensional Josephson Array

We examine the phase diagram of an ordered one-dimensional Josephson array of small grains. The average grain charge in such a system can be tuned by means of gate voltage. At small grain-to-grain conductance, this system is strongly correlated because of the charge discreteness constraint (Coulomb blockade). At the gate voltages in the vicinity of the charge degeneracy points, we find a new intermediate phase equivalent to a repulsive Luttinger liquid, which separates the charge density wave state from the superconducting state. The existence of this phase can be probed by measuring the Josephson current through a chain containing one weaker link.