Effective Action and Renormalization Group Flow of Anisotropic Superconductors

Abstract

We calculate the effective action of a superconductor, without assuming that either the electron-electron potential or the Fermi surface obey rotational invariance. This approach leads to the same gap equation and equilibrium free energy as more conventional methods. The results are used to obtain the Gell-Mann - Low renormalization group equations for the electron-electron potential.