QUANTUM PHASE-DIAGRAMS IN PERIODIC AND GLASSY ARRAYS OF ULTRA-SMALL JOSEPHSON-JUNCTIONS

Recent advances in submicrometer technology have made it possible to f abricate relatively large arrays of ultrasmall Josephson junctions. Th e areas of these junctions can vary from a few microns to submicron si zes. Under these circumstances the long-range phase coherent propertie s of the Josephson junction arrays crucially depend on the interplay b etween the Josephson and charging energies. In this paper we will pres ent a brief review of some of our recent results on the relevance of u ltra-small capacitances in periodic and disordered arrays as well as t he evidence for or against a low-temperature quantum-fluctuation-induc ed phase transition (QUIT), both for zero and full frustration. We als o discuss results from a study of a quantum superconducting glass mode l, obtained from using different approximate analytic techniques. We m ention a direct comparison between our results and those obtained in p eriodic arrays.