  The Dicke spin-boson model is composed by a single bosonic mode and an
ensemble of $N$ identical two-level atoms. Assuming thermal equilibrium with a
reservoir at temperature $\beta^{-1}$, we consider the situation where the
coupling between the bosonic mode and the atoms generates resonant and
non-resonant processes. The thermodynamic of the model is investigated. Next we
introduce dipole-dipole interaction between the atoms. We investigate the
transition from fluorescent to super-radiant phase and the quantum phase
transition in a situation where the dipole-dipole interaction between the atoms
generates entangled states in the atomic system. We proved that, the critical
behavior is not modified by the introduction of the dipole-dipole interaction.
