Colossal Brownian yet non-Gaussian diffusion induced by nonequilibrium noise

TL;DR

This paper introduces a novel form of Brownian motion where particles exhibit Gaussian-like spreading with exponential tails in their increments, caused by external non-thermal noise, leading to colossal diffusion enhancement.

Contribution

It demonstrates a new mechanism for non-Gaussian diffusion driven by external noise in a periodic potential, distinct from previous models based on space or time-dependent diffusivity.

Findings

Mean square displacement grows linearly with time.

Probability density for particle spreading is Gaussian-like.

Increment distribution has an exponential tail, causing colossal diffusion.

Abstract

We report on novel Brownian, yet non-Gaussian diffusion, in which the mean square displacement of the particle grows linearly with time, the probability density for the particle spreading is Gaussian-like, however, the probability density for its position increments possesses an exponentially decaying tail. In contrast to recent works in this area, this behaviour is not a consequence of either a space or time-dependent diffusivity, but is induced by external non-thermal noise acting on the particle dwelling in a periodic potential. The existence of the exponential tail in the increment statistics leads to colossal enhancement of diffusion, surpassing drastically the previously researched situation known under the label of "giant" diffusion. This colossal diffusion enhancement crucially impacts a broad spectrum of the first arrival problems, such as diffusion limited reactions governing transport in living cells.