Competitive stochastic noises in coherently driven two-level atoms and quantum interference

A system of coherently driven two-level atoms is analysed in the presence of two independent stochastic perturbations: one due to collisions and a second due to phase fluctuations of the driving field. The behaviour of the quantum interference induced by the collisional noise is considered in detail. The quantum-trajectory method is utilized to reveal the phase correlations between the dressed states involved in the interfering transition channels. It is shown that the quantum interference induced by the collisional noise is remarkably robust against phase noise. This effect is due to the fact that the phase noise, similarly to collisions, stabilizes the phase difference between the dressed states.