  In this article, we are interested in a spin model including the quantized
electromagnetic field (photons). With this model of quantum electrodynamics
(QED) related to nuclear magnetic resonance (NMR) we give explicit quantum
radiative corrections of the time evolution for the spin observables, for the
electric and magnetic fields observables and for the photon number observable.
As a by-product, this underlines that Bloch equations are the semiclassical
limit of the model in QED considered here. In addition, transition
probabilities for the same model are investigated.
