Dynamic Stark effect, light emission, and entanglement generation in a laser-driven quantum optical system

Abstract

We calculate the emission spectra, the Glauber $g^{(2)}$ function, and the entanglement of formation for a few two-level emitters coupled to a single cavity mode and subject to an external laser-excitation. To evaluate these quantities we couple the system to environmental degrees of freedom which leads to dissipative dynamics. Because of the periodic time-dependence of the system Hamiltonian, the coefficients of the (Markovian) master equation are constant if Floquet states are used as the computational basis. Studying the emission spectra we show that the dynamic Stark effect, i.e., the shift of spectral lines, first appears in the second order of the laser intensity. For the Glauber function, we find clearly distinguished parameter regimes of super- and sub-Poissonian light emission and explain the additional features appearing for finite laser intensity in terms of the quasienergy spectrum of the driven emitter-cavity system. Finally, we analyze the temperature and emitter-cavity coupling regimes where entanglement among the emitters is generated, and show that the laser-excitation leads to a decrease of entanglement.