Proper choice of the gauge in superconductors allowing a new formulation of the vortex line free energy: Applications

We determine a gauge allowing the order parameter to be real in the mixed state of type II superconductors although flux quantization is respected. The Ginzburg-Landau equations written in this peculiar gauge are then derived to obtain a new formulation of the vortex line free energy. The result is first tested in the simple case of an isolated vortex in an infinite superconductor and then used to compare the superheating field at a normal-superconducting boundary with that at a vacuum-superconducting boundary.