Quantum theory of an electromagnetic observer: classically behaving macroscopic systems and emergence of classical world in quantum electrodynamics

TL;DR

This paper demonstrates that mesoscopic quantum electrodynamics can be reformulated in a classical-like framework, revealing how classical behavior emerges from quantum systems and impacting quantum measurement theory.

Contribution

It shows that mesoscopic quantum electrodynamics shares its structure with classical stochastic electrodynamics, allowing classical reasoning to replace quantum considerations without loss of generality.

Findings

Reformulation of mesoscopic quantum electrodynamics without Planck's constant

Classical stochastic electrodynamics and quantum electrodynamics share dynamical structure

Implications for quantum measurement theory and classical emergence

Abstract

Quantum electrodynamics under conditions of distinguishability of interacting matter entities, and of controlled actions and back-actions between them, is considered. Such "mesoscopic quantum electrodynamics" is shown to share its dynamical structure with the classical stochastic electrodynamics. In formal terms, we demonstrate that all general relations of the mesoscopic quantum electrodynamics may be recast in a form lacking Planck's constant. Mesoscopic quantum electrodynamics is therefore subject to "doing quantum electrodynamics while thinking classically," allowing one to substitute essentally classical considerations for quantum ones without any loss in generality. Implications of these results for the quantum measurement theory are discussed.