Causal signal transmission by quantum fields. Quantum electrodynamics in response representation

Abstract

Using electromagnetic interaction as an example, response transformations [L.P. and S.S., Ann.Phys. 323, 1963, 1989 (2008), 324, 600 (2009)] are applied to the standard perturbative approach of quantum field theory. This approach is rewritten in the form where the place of field propagators is taken by the retarded Green function of the field. Unlike in conventional quantum-field-theoretical techniques, the concept of space-time propagation of quantized field is built into our techniques.

This manuscript is an early version of what later became Refs. [1,2]. Some of the discussions were also included in [3-5]. The "narrow-band" case remains unpublished