Dynamical renormalization of the Jaynes-Cummings model

The effect of counter-rotating terms on the Jaynes-Cummings model of a two-level atom is studied. The technique of dynamical renormalization is used to generate a hybrid gauge which exists between the d.E and p.A gauges. The resulting truncated Hamiltonian including counter-rotating type terms has an interaction that couples the atomic inversion to the field intensity. This Hamiltonian is exactly soluble, resulting in a phase-dependent inversion, together with simultaneous frequency and refractive-index shifts.