GENERALIZATION OF THE CLASSICAL FLUCTUATION-DISSIPATION RELATION TO THE PRESENCE OF DYNAMICAL PROCESSES

We generalize the fluctuation-dissipation relation (FDR) to the cases when dynamical processes are explicitely accounted for as: (i) inter-c ollisional and (ii) intra-collisional events. In both cases the functi on g(omega) describing FDR exhibits peculiar frequency dependences. In the former case, which corresponds to nonequilibrium Markovian transp ort, the frequency dependence appears already at low frequencies and t he highest-frequency limit g(proportional to) keeps a white spectrum. In the latter case. when the intra-collisional dynamics is accounted f or, the highest-frequency spectrum of g(omega) is modified in such a w ay that the ultraviolet catastrophe, associated with the total noise p ower transferred outside by the system, is removed already under class ical conditions.