Dynamics of a dissipative two-qubit system interacting non-linearly with a generalized field: Entanglement and mixedness

In this paper, two identical qubits nonlinearly interacting with a generalized coherent cavity field is explored. The dipole-dipole interaction between the two qubits is considered. Analytical solution of the master equation is derived. Mixedness and entanglement are analyzed through the study of entropies and negativity in all bipartitions of the dissipative system. We show that these measures are very sensitive not only to the dissipation rate, but also to the dipole-dipole parameter. Moreover, we notice that the system presents entanglement sudden birth and death.