Dissipation and entanglement dynamics for two interacting qubits coupled to independent reservoirs

We derive the master equation of a system of two coupled qubits by taking
into account their interaction with two independent bosonic baths. Important
features of the dynamics are brought to light, such as the structure of the
stationary state at general temperatures and the behaviour of the entanglement
at zero temperature, showing the phenomena of sudden death and sudden birth
as well as the presence of stationary entanglement for long times. The model
presented here is quite versatile and can be of interest in the study of both
Josephson junction architectures and cavity-QED.