Nonequilibrium quantum electrodynamics

We employ the influence functional technique to trace out the photonic contribution from full quantum electrodynamics. The reduced density matrix propagator then is constructed for the electron field. We discuss the role of time-dependent renormalization in the propagator and focus our attention on the possibility of obtaining a dynamically induced superselection rule. As a final application of our formalism, we derive the master equation for the case of the field being in a one-particle state in the nonrelativistic regime and discuss whether electromagnetic vacuum fluctuations are sufficient to produce decoherence in a position basis.