Quantum dynamics of the field in two-photon absorbing medium

The process of simultaneous absorption of two photons in a medium is considered. The medium is perturbed externally in the two-photon parametric way. With the use of numerical simulation of quantum trajectories of the system the Wigner functions of the field states are calculated. It is shown that the steady state of the field depends strongly on the amplitude of the initial coherent state of the system. A strong dependence of the steady state on the time of the first two-photon quantum jump of the system is shown to be possible