Title: Random gauge models of the superconductor-insulator transition in two-dimensional disordered superconductors,
Abstract: We study numerically the superconductor-insulator transition in
two-dimensional inhomogeneous superconductors with gauge disorder, described by
four different quantum rotor models: a gauge glass, a flux glass, a binary
phase glass and a Gaussian phase glass. The first two models, describe the
combined effect of geometrical disorder in the array of local superconducting
islands and a uniform external magnetic field while the last two describe the
effects of random negative Josephson-junction couplings or $\pi$ junctions.
Monte Carlo simulations in the path-integral representation of the models are
used to determine the critical exponents and the universal conductivity at the
quantum phase transition. The gauge and flux glass models display the same
critical behavior, within the estimated numerical uncertainties. Similar
agreement is found for the binary and Gaussian phase-glass models. Despite the
different symmetries and disorder correlations, we find that the universal
conductivity of these models is approximately the same. In particular, the
ratio of this value to that of the pure model agrees with recent experiments on
nanohole thin film superconductors in a magnetic field, in the large disorder
limit.