U(1) Field Theory in the Limit of a Large Coupling Constant
  We consider a massive fermion interacting with a U(1) gauge field in the limit of a large coupling constant. It is found that the current has a generalized London term that can originate massive excitations for two of the three components of the gauge field, which disappear for a free particle at rest. The origin of the superconductive term is due to a partial breaking of the gauge symmetry in the limit of a large coupling constant. Beside, the scalar potential generated by the particle, the only component of the gauge field that keeps gauge invariance, increases with the square of the distance. These results should give a path towards the derivation of quark confinement from QCD. 
Marco Frasca