Quantum phase diagrams in periodic and glassy arrays of ultra-small Josephson junctions

Abstract

Recent advances in submicrometer technology have made it possible to fabricate relatively large arrays of ultra-small Josephson junctions. The areas of these junctions can vary from a few microns to submicron sizes. Under these circumstances the long-range phase coherent properties of the Josephson junction arrays crucially depend on the interplay between the Josephson and charging energies. In this paper we will present a brief review of some of our recent results on the relevance of ultra-small capacitances in periodic and disordered arrays as well as the evidence for or against a low-temperature quantum0fluctuation-induced phase transition (QUIT), both for zero and full frustration. We also discuss results from a study of a quantum superconducting glass model, obtained from using different approximate analytic techniques. We mention a direct comparison between our results and those obtained in periodic arrays.