Equivalence between the Fock-Schwinger Gauge and the Feynman Gauge

The principal attraction of the Fock-Schwinger (FS) gauge is that the gauge potentials are completely determined in terms of the electromagnetic fields by an inversion formula once the condition x·A=0 is fixed. We have reformulated the FS gauge propagator, first derived by Kummer and Weiser, in a more useful and manageable form and applied it to perturbation calculations in spinor and scalar QED and QCD. In that way we have been able to verify the on-mass-shell equivalence of these calculations to the covariant Feynman gauge.