Noise Transformation in Nonlinear System with Intensity Dependent Phase Rotation

The statistical behavior of a nonlinear system described by a mapping with phase rotation is studied. We use the Kolmogorov-Chapman equations for the multi-time probability distribution functions for investigation of dynamics under the external noise perturbations. We find a stationary solution in the long-time limit as a power series around a state with complete phase randomization (”phase mixing”). The Ornstein-Uhlenbeck and Kubo-Andersen models of noise statistics are considered; the conditions of convergence of the power expansions are established.