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Book ChapterDOI

Fokker-Planck Equation

Hannes Risken
- pp 63-95
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TLDR
In this paper, an equation for the distribution function describing Brownian motion was first derived by Fokker [11] and Planck [12] and it is shown that expectation values for nonlinear Langevin equations (367, 110) are much more difficult to obtain.
Abstract
As shown in Sects 31, 2 we can immediately obtain expectation values for processes described by the linear Langevin equations (31, 31) For nonlinear Langevin equations (367, 110) expectation values are much more difficult to obtain, so here we first try to derive an equation for the distribution function As mentioned already in the introduction, a differential equation for the distribution function describing Brownian motion was first derived by Fokker [11] and Planck [12]: many review articles and books on the Fokker-Planck equation now exist [15 – 15]

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Citations
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Physics of open systems

TL;DR: In this paper, the authors outline some views which may be easily overlooked in practice and then ultimately continue to point out a general principle that may be very fundamental for all branches of natural science, the so-called maximum entropy principle worked out by Jaynes.
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Functional Wigner representation of quantum dynamics of Bose-Einstein condensate

TL;DR: In this paper, the authors developed a method of simulating the full quantum field dynamics of multi-mode multi-component Bose-Einstein condensates in a trap using truncated Wigner representation.
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Mechanisms of Dispersion in a Porous Medium

TL;DR: In this article, the authors studied the mechanisms of dispersion in the laminar flow through the pore space of a $3$-dimensional porous medium and quantified systematically in the framework of a time-domain random walk for the motion of marked elements (particles) of the transported material quantity.
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Correlated Fluctuations in Strongly Coupled Binary Networks Beyond Equilibrium

TL;DR: The systematic cumulant expansion for kinetic binary (Ising) threshold units with strong, random and asymmetric couplings presented here goes beyond mean-field theory and is applicable outside thermodynamic equilibrium; a system of approximate non-linear equations predicts average activities and pairwise covariances in quantitative agreement with full simulations down to hundreds of units.
References
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Journal ArticleDOI

Fluctuations and Irreversible Processes

TL;DR: In this paper, the probability of a given succession of (nonequilibrium) states of a spontaneously fluctuating thermodynamic system is calculated, on the assumption that the macroscopic variables defining a state are Gaussian random variables whose average behavior is given by the laws governing irreversible processes.
Journal ArticleDOI

The Radiation Theories of Tomonaga, Schwinger, and Feynman

TL;DR: In this article, a unified development of the subject of quantum electrodynamics is outlined, embodying the main features both of the Tomonaga-Schwinger and of the Feynman radiation theory.
Journal ArticleDOI

Covariant formulation of non-equilibrium statistical thermodynamics

TL;DR: In this paper, the diffusion matrix of the Fokker Planck equation is used as a contravariant metric tensor in phase space, and the covariance of the Langevin-equations and the fokker equation is demonstrated.
Journal ArticleDOI

Approximation of the Linear Boltzmann Equation by the Fokker-Planck Equation

TL;DR: In this article, the first two terms of the Kramers-Moyal expansion of the Fokker-Planck equation were used to approximate the linear Boltzmann integral operator.