Lack of anomalous diffusion in linear translationally-invariant systems determined by only one initial condition

Abstract

It is shown that as far as the linear diffusion equation meets both time- and space- translational invariance, the time dependence of a moment of degree $α$ is a polynomial of degree at most equal to $α$, while all connected moments are at most linear functions of time. As a special case, the variance is an at most linear function of time.

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