Fluctuation-dissipation theorems for classical processes

For certain types of classical processes a fluctuation-dissipation theorem (FDT) holds. The validity of such a theorem is preserved in each order of mass renormalization in the perturbation scheme recently developed by Martin, Siggia, and Rose (MSR). As a consequence, whenever the response function can be expressed in terms of the two-point correlation function via a FDT, the perturbation scheme of MSR simplifies considerably. Especially, it reduces to the scheme constructed by Kawasaki for random processes obeying detailed balance which are (i) linearly damped and (ii) linearly driven by Gaussian white noise.