A quantum-electrodynamic theory of spontaneous emission in the presence of a dielectric has been worked out, and formulas are presented for the change in the lifetime and the Lamb shift of a two-level atom, as a result of the presence of a dielectric. Curves are given for the behavior of the damping as a function of the distance of the atom from the interface. The frequency shift for the case of a conductor is also evaluated.

• Received 19 December 1973

DOI:https://doi.org/10.1103/PhysRevLett.32.703