Quantum Vector Fields In Inflation

Accelerated expansion during inflation does not amplify vector fields on account of their conformal coupling to gravity. Nonetheless, the effects of the expansion can be communicated to them by interactions. These can come about in two ways: either at the classical level by coupling to matter field condensates, or at the quantum level via loops containing non-conformally coupled scalars or gravitons. Quantifying quantum corrections requires working out vector propagators that are used to compute loop corrections. In the first part of the talk we will present the construction of massless vector propagator in de Sitter in the general covariant gauge, and how the Ward identity forces it to break de Sitter invariance. The second part of the talk will be devoted to symmetry-breaking scalar electrodynamics and loop corrections that drive the evolution of the scalar condensate away from its classical attractor.