Microscopic foundation of macroscopic quantum optics

A limited equivalence between microscopic and macroscopic quantizations of the electromagnetic field in a dielectric is established. We demonstrate that macroscopic canonical quantization of the electromagnetic field in an idealized absorptionless dielectric is equivalent to microscopic quantization followed by the elimination of the material degrees of freedom in the limit of an adiabatic response of the oscillators averaged over a quantization volume. We demonstrate that a loss of generality and extensibility accompanies the reduction of the full microscopic theory.