Quantum critical phenomena in charged superconductors

We study the effect of Coulomb interactions on the onset of superconductivity with increasing intergrain coupling in granular systems at T=0. We show that in three dimensions (3D) the onset transition is described by Euclidean scalar electrodynamics, and so can be either first or second order, depending on parameters. A renormalization-group analysis indicates that in 2D the transition can either be first order, or second order with 3D-XY-like critical behavior. In 1D Coulomb forces are shown to destroy the superconducting state. © 1988 The American Physical Society.