Sub-radiation versus super-radiation from a system of spatially distributed two-level atoms

We study exactly solvable Dicke-like model describing a system of spatially distributed two-level atoms coupled to a single mode cavity field. We study the model in one excitation sub-space, when the field is supposed to be intitially in the vacuum state and just one atom of the atomic sample is excited. We show that depending on the particular spatial distribution of atoms the system under consideration can exhibit super-radiation or sub-radiation. Moreover, we investigate the dynamics of the two-atom system interacting with the cavity field initially prepared in an arbitrary state. Co-operative effects are discussed in this case. (orig.)