Radiative properties of atoms near a conducting plane: An old problem in a new light

We examine the level shifts and radiation rates of an atom near an infinite, perfectly conducting plane. Following the work of Dalibard, Dupont-Roc, and Cohen-Tannoudji [J. Phys. (Paris) 43, 1617 (1982); 45, 637 (1984)], we distinguish between the effects of radiation reaction and vacuum fluctuation. This separation provides some new physical insight into the nature of ``cavity'' modifications of atomic properties. In particular, we are able to identify the Casimir interaction as entirely due to the vacuum fluctuations.