Assume that we have a two-level atom is prepared initially in the state |g> interacts locally with a cavity mode prepared in the state In >. If the Hamilton which describes this system is given by: H = hwata+hwo+h(o+a+o_at), where w, wo are the frequencies of the atom and the field, and λ is the coupling constant between the atom and the field. Find the state which describe the atom-field system at any time t > 0.