Massive Electrodynamics

Abstract

The relation between gauge invariance, canonical quantization, and the photon mass is examined. It is found that gauge invariance does not require the bare photon mass to be zero. In fact, quantization in an arbitrary covariant gauge is only possible for massive photons. This is a generalization of the usual Fermi procedure. A similar generalization of the conventional Coulomb gauge quantization leads to a gaugeinvariant, but noncovariant, theory of massive transverse photons.