Quantum coherence and phase transitions in granular superconductors with dissipation. II. Effect of disorder

Abstract

We study the effect of disorder on a superconducting phase transition in granular arrays with dissipation. It is shown that, for a quite weak Gaussian disorder, this effect does not lead to a qualitative change of the phase diagram. Local quantum fluctuations suppress Cooper pair tunneling for a part of Josephson junctions and thus effectively increase disorder. For strongly disordered systems, the critical resistance which corresponds to a dissipative phase transition is found to be universal for a wide range of parameters.