PUB - Publikationen an der Universität Bielefeld

We study numerically the phase structure of the Ginzburg-Landau model, with particular emphasis on mass measurements. There is no local gauge-invariant order parameter, but we find that there is a phase transition characterized by a vanishing photon mass. For type-I superconductors the transition is of first order. For type-II, a first-order transition is excluded by susceptibility analysis, but the photon correlation length is compatible with second-order critical behavior with nu similar to 1/2. The scalar mass, in contrast, does not show clear critical behavior in the type-II regime for V-->infinity, contrary to the conventional picture.