I want to calculate the density matrix element's average over all the realization of Gaussian colored noise when the atomic system is coupled to the said noise. I know how to do it for atomic energy levels coupled to white Gaussian noise. The problem is with the Non-Markovian Gaussian colored noise. Can anyone tell me how to do this or can suggest some references? Do I need to use the stochastic Schrodinger equation or anything else? Do I need to use the Novikov theorem in order to calculate the noise average of the density matrix element as it is for white Gaussian noise, if yes how to calculate the functional derivative that will appear in the Novikov theorem?