Infraparticle quantum fields and the formation of photon clouds

Jens Mund, Karl-Henning Rehren, Bert Schroer
September 21, 2021
A non-perturbative and exactly solvable quantum field theoretical model for a "dressed Dirac field" is presented, that exhibits all the kinematical features of QED: an appropriate delocalization of the charged field as a prerequisite for the global Gauss Law, superselected photon clouds (asymptotic expectation values of the Maxwell field), infraparticle nature of charged particles that cannot be separated from their photon clouds, broken Lorentz symmetry. The model serves as an intermediate leg on a new roadmap towards full QED, formulated as an off-shell theory, i.e., including a perturbative construction of its interacting charged fields. It also fills a gap in recent discussions of the "Infrared Triangle", and points the way towards a new scattering theory for theories with massless particles of helicity $\geq 1$, in which infraparticles can be described at the level of charged fields, rather than just states.