Abstract
Starting from a self-consistent solution of the Maxwell equations, we present a theoretical investigation of the retarded electromagnetic response of a single-electron quantum dot with an isotropic parabolic confinement potential. It is shown that the correct expressions for the spontaneous decay rate and the Lamb shift are obtained from a general resonance condition. We derive an expression for the absorption cross section and compare the result to the expressions obtained within the Born approximation and dipole approximation. A numerical comparison of the cross sections is presented, and, in particular, the size dependence of the deviations is studied. DOI: http://dx.doi.org/10.1103/PhysRevB.52.4670 © 1995 The American Physical Society