Effects of laser fluctuations on the driven Dicke model

The exact steady-state solution is presented for the reduced density operator for a model of N identical two-level atoms on a single site (the Dicke model) driven by a laser field with phase fluctuations. Exact expressions are given for the phase averaged atomic observables and atomic correlation functions of arbitrary order. Results show that the inclusion of phase fluctuations tends to smooth the discontinuities in the observables and their correlation functions found in the non-fluctuating resonant case. Quantum fluctuations are also reduced due to the effects of the phase fluctuations and with increasing N, the atomic observables tend to assume their semi-classical value.