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Abstract
Universal properties of the zero temperature superconductor-insulator
transition in two-dimensional amorphous films are studied by extensive Monte
Carlo simulations of bosons in a disordered medium. We report results for both
short-range and long-range Coulomb interactions for several different points in
parameter space. In all cases we observe a transition from a superconducting
phase to an insulating Bose glass phase. {}From finite-size scaling of our
Monte Carlo data we determine the universal conductivity $\sigma^*$ and the
critical exponents at the transition. The result $\sigma^* = (0.55 \pm 0.06)
(2e)^2/h$ for bosons with long-range Coulomb interaction is roughly consistent
with experiments reported so far. We also find $\sigma^* = (0.14 \pm 0.03)
(2e)^2/h$ for bosons with short-range interactions.
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