Dressing the Lorentz atom

We investigate the effects of the electromagnetic vacuum field on a harmonically bound electron. We show that in the electric-dipole approximation the model atom couples only to an effective one-dimensional electric field. In a simplified form, in which the problem is reduced to a single spatial dimension, we determine, analytically, the form of the ground state and discuss the significance of this.
Comment: 11 pages, 2 figures. This article is a contribution to the special issue of Physics, "Matter-Radiation Interactions -- In Memory of Professor Francesco Saverio Persico"