Limited thermalization for the Markov mean-field model of N atoms in thermal field

A Markov mean-field model of N n-level atoms interacting with a thermal electro-magnetic field is discussed. The exact form of the asymptotic states for the atomic system is established using group theoretical methods. These states depend strongly on the initial conditions and generally differ from the equilibrium state. It is a collective phenomenon due to the interatomic interference effects and may be treated as an analogon of subradiance observed in spontaneous emission.