• DOI:10.1088/0034-4885/29/1/306
• Corpus ID: 250892844

The fluctuation-dissipation theorem

@article{Kubo1966TheFT,
  title={The fluctuation-dissipation theorem},
  author={R Kubo},
  journal={Reports on Progress in Physics},
  year={1966},
  volume={29},
  pages={255 - 284}
}

• R Kubo
• Published 1966
• Mathematics, Physics
• Reports on Progress in Physics

The linear response theory has given a general proof of the fluctuation-dissipation theorem which states that the linear response of a given system to an external perturbation is expressed in terms of fluctuation properties of the system in thermal equilibrium. This theorem may be represented by a stochastic equation describing the fluctuation, which is a generalization of the familiar Langevin equation in the classical theory of Brownian motion. In this generalized equation the friction force becomes retarded or frequency-dependent and the random force is no more white. They are related to each other by a generalized Nyquist theorem which is in fact another expression of the fluctuation-dissipation theorem. This point of view can be applied to a wide class of irreversible process including collective modes in many-particle systems as has already been shown by Mori. As an illustrative example, the density response problem is briefly discussed.