Causal signal transmission by quantum fields. Electromagnetic interaction of distinguishable devices and the optical equivalence theorem

TL;DR

This paper extends phase-space techniques to electromagnetic interactions of distinguishable devices, generalizing the optical equivalence theorem to facilitate semiclassical analysis of quantum electrodynamics.

Contribution

It introduces a generalized optical equivalence theorem applicable to interacting electromagnetic fields beyond the rotating wave approximation.

Findings

Enables reduction of quantum problems to semiclassical considerations

Provides a framework for analyzing distinguishable device interactions

Extends phase-space techniques to broader electromagnetic interactions

Abstract

Generalised phase-space techniques for electromagnetic interactions beyond the rotating wave approximation [L.P. and S.S., arXiv:1104.3825 (2011)] is applied to interactions of distinguishable devices. The paper is built around the concept of "doing quantum electrodynamics while thinking classically," which is a generalisation of Sudarshan's renowned optical equivalence theorem [E.C.G. Sudarshan, Phys. Rev. Lett. 10, 277 (1963)] to the interacting electromagnetic field. This concept allows one to reduce inherently quantum problems to semiclassical considerations.