We calculate the expectation value of the coincident product of two field
strength tensors at two loop order in scalar electrodynamics on de Sitter
background. The result agrees with the stochastic formulation which we have
developed in a companion paper [2] for the nonperturbative resummation of
leading logarithms of the scale factor. When combined with a previous
computation of scalar bilinears [1], our current result also gives the two loop
stress-energy tensor for inflationary scalar electrodynamics. This shows a
secular decrease in the vacuum energy which derives from the vacuum
polarization induced by the inflationary production of charged scalars.Comment: 62 pages, 1 eps figur