Time-Correlation Function for Periodically-Forced Nonlinear Stochastic System
Jinghui Li, He Kai-Fen, Huang Zuqia · Communications in Theoretical Physics · 1998
The equilibrium time-correlation function for a general cosine-forced stochastic system are calculated respectively by the perturbation theory and the linear response theory. The results obtained by the two theories are basically identical. By calculation we find that it has two terms. One is the original time-correlation function (in the case when the external signal does not exist). The other is caused by the perturbing external signal. The two terms have the same relaxation time, and the latter has oscillator behavior.