Charged States In A Semiclassical Model Of Infrared Gupta-Bleuler Quantum Electrodynamics

Abstract: We address the problem of the identification and characterization of charged states within local and covariant quantizations of abelian gauge theories, focusing on a semiclassical model of infrared Gupta-Bleuler Quantum Electrodynamics, based on the Bloch-Nordsieck approximation and formulated in Feynman's gauge. The GNS construction over suitable functionals yields positive subspaces of the indefinite-metric space of the model; charged states with Li\'enard-Wiechert space-like asymptotics can then be constructed via an automorphism of the algebra of observables implementing Gauss' law. Finally, by an analysis of the localization properties of the corresponding expectations over the asymptotic electromagnetic fields, it is shown that such states identify an infrared-minimal charge class in the sense of Buchholz.