Microscopic approach to field dissipation in the Jaynes–Cummings model

We use the microscopic derivation of the Jaynes–Cummings model master equation under field losses to study the dynamics of initial field-qubit states in the single-excitation manifold and beyond. We show that field-qubit detuning, as well as finite temperature, modify the effective decay rate of the system using measures like field-qubit purity and concurrence for the case of one-excitation, and for initial Fock states for more excitations. For initial semi-classical states of the field, we show that the microscopic approach, in phase space, provides an evolution to thermal equilibrium that is smoother than the one provided by the standard phenomenological approach. (paper)