Charged particles in external fields. I. Classical theory

Publisher Website
Google Scholar
Abstract
A general perturbation theory is presented which can be used to study the interaction of relativistic charged particles with external fields. The theory is applied to the classical Dirac and Klein–Gordon equations. For external fields which are test functions on space–time retarded and advanced fundamental solutions are shown to exist, and their relation with the evolution operator is established. The S operator is shown to be Lorentz covariant and causal. The implementability in Fock space of the evolution is considered. It is shown that electric fields give rise to an implementable evolution while other kinds of fields in general do not.