Nonextensive diffusion as nonlinear response

Abstract

The porous media equation has been proposed as a phenomenological ``non-extensive'' generalization of classical diffusion. Here, we show that a very similar equation can be derived, in a systematic manner, for a classical fluid by assuming nonlinear response, i.e. that the diffusive flux depends on gradients of a power of the concentration. The present equation distinguishes from the porous media equation in that it describes \emph{% generalized classical} diffusion, i.e. with $r/\sqrt{D}t$ scaling, but with a generalized Einstein relation, and with power-law probability distributions typical of nonextensive statistical mechanics.

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• Superstatistics
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Cited by in corpus (3)

• Generalized Diffusion
• Nonlinear diffusion from Einstein's master equation
• Statistics of precursors to fingering processes