arXiv:quant-ph/9906001
QED in the Presence of Arbitrary Kramers-Kronig Dielectric Media
Stefan Scheel, D.‐G. Welsch
Abstract
The phenomenological Maxwell field is quantized for arbitrarily space- and frequency-dependent complex permittivity. The formalism takes account of the Kramers--Kronig relation and the dissipation-fluctuation theorem and yields the fundamental equal-time commutation relations of QED. Applications to the quantum-state transformation at absorbing and amplifying four-port devices and to the spontaneous decay of an excited atom in the presence of absorbing dielectric bodies are discussed.