Quantum radiation in dielectric media with dispersion and dissipation

TL;DR

This paper develops a microscopic model for quantum electrodynamics in dispersive, dissipative dielectric media, enabling precise calculations of photon creation due to dissipation switching, revealing novel partner particle behavior.

Contribution

It introduces a generalized Hopfield model for media with dispersion and dissipation, allowing ab initio quantum electrodynamics analysis in time-dependent backgrounds.

Findings

Photon creation depends on the dissipation switching function.

Partner particles are environmental excitations, not medium photons.

Photon production can surpass that from refractive index variations.

Abstract

By a generalization of the Hopfield model, we construct a microscopic Lagrangian describing a dielectric medium with dispersion and dissipation. This facilitates a well-defined and unambiguous $\textit{ab initio}$ treatment of quantum electrodynamics in such media, even in time-dependent backgrounds. As an example, we calculate the number of photons created by switching on and off dissipation in dependence on the temporal switching function. This effect may be stronger than quantum radiation produced by variations of the refractive index $\Delta n(t)$ since the latter are typically very small and yield photon numbers of order $(\Delta n)^2$. As another difference, we find that the partner particles of the created medium photons are not other medium photons but excitations of the environment field causing the dissipation (which is switched on and off).