Phase transition in random superconductors

A phenomenological model of an inhomogeneous superconductor is studied using the method of an effective Hamiltonian. Using renormalization group arguments and the epsilon expansion it is shown that for a realistic size of fluctuations of the local Tsub(c) the phase transition is smeared. For small a sharp phase transition with enhanced critical fluctuations above Tsub(c) is predicted. (author)