Resonances for Atoms in Dipole approximation of non-relativistic QED

Abstract: We consider atoms or molecules coupled to the quantized electromagnetic radiation field in a dipole approximation. We show the existence of ground states and resonance states in situations where the eigenvalues are degenerate and protected by a symmetry group. We show that ground states and resonance states as well as their energies depend analytically on the coupling constant. Our results are an application of the result in [20], which in turn is obtained using operator theoretic renormalization.