We present a Monte Carlo study of the d = 3 gauge glass and the XY-spin glass models in the vortex representation. We investigate the critical behavior of these models by a scaling analysis of the linear resistivity and current-voltage characteristics, both in the limits of zero and strong screening of the vortex-interactions. Without screening, both models show a glass transition at a finite temperature and, within the numerical accuracy, exhibit the same critical exponents: z ≈ 3.1 and ν = 1.3 ± 0.3. With strong screening, the finite temperature glass transition is destroyed in both cases and the same exponent ν = 1.05 ± 0.1 is found at the resulting zero temperature transition.

We present a finite temperature Monte Carlo study of the XY-model in the vortex representation, and study its dynamical critical behavior in two limits. The first neglects magnetic field fluctuations, corresponding to the absence of screening, which should be a good approximation in high Tc superconductors (κ → ∞) except extremely close to the critical point. Here, from finite size scaling of the linear resistivity we find the dynamical critical exponent of the vortex motion to be z ≈ 1.5. The second limit includes magnetic field fluctuations in the strong screening limit (κ → 0) corresponding to the true asymptotic inverted XY critical regime, where we find the unexpectedly large value z ≈ 2.7. We compare these results, obtained from dissipative dynamics in the vortex representation, with the universality class of the corresponding model in the phase representation with propagating (spin wave) modes. We also discuss the effect of disorder and the relevance of our results for experiments.

We investigate the critical behavior of the gauge glass model for the vortex glass transition in threedimensional superconductors, including screening of the interaction between vortices. A Monte Carlo study of the linear resistivity and a scaling analysis of current-voltage characteristics indicates that screening destroys the finite-temperature transition found earlier when screening was neglected. The correlation length exponent at the resulting zero temperature transition is found to be ν = 1.05±0.1.

We study the properties of the Bose glass phase of localized flux lines in irradiated superconductors near the matching field B F . Repulsive vortex interactions destroy the Mott insulator phase predicted to occur at B B F . For ratios of the penetration depth to average defect distance l͞d # 1, remnants of the Mott insulator singularities remain visible in the magnetization, the bulk modulus, and the magnetization relaxation, as B is varied near B F . For l $ d, the ensuing weakly pinned Bose glass is characterized by a soft Coulomb gap in the distribution of pinning energies. [S0031-9007(97)03391-7]