We describe the absorption by the walls of a quantum electrodynamical cavity as a process during which the elementary excitations (photons) of an internal mode of the cavity exit by tunneling through the cavity walls. We estimate by classical methods the survival time of a photon inside the cavity and the quality factor of its mirrors.
V. Debierre, G. Demésy, T. Durt, A. Nicolet, B. Vial, and F. Zolla. Absorption in quantum electrodynamics cavities in terms of a quantum jump operator. Phys. Rev. A 90, p. 033806, Sept. 2014. DOI | arXiv