Diffusion with a broad class of stochastic diffusion coefficients

Fuente: arXiv
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Main Authors: Uchida, Go, Washizu, Hitoshi, Miyoshi, Hiromi
Format: Preprint
Published: 2023
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_version_ 1866914831998648320
author Uchida, Go
Washizu, Hitoshi
Miyoshi, Hiromi
author_facet Uchida, Go
Washizu, Hitoshi
Miyoshi, Hiromi
contents In many physical or biological systems, diffusion can be described by Brownian motions with stochastic diffusion coefficients (DCs). In the present study, we investigate properties of the diffusion with a broad class of stochastic DCs with a novel approach. We show that for a finite time, the propagator is non-Gaussian and heavy-tailed. This means that when the mean square displacements are the same, for a finite time, some of the diffusing particles with stochastic DCs diffuse farther than the particles with deterministic DCs or exhibiting a fractional Brownian motion. We also show that when a stochastic DC is ergodic, the propagator converges to a Gaussian distribution in the long time limit. The speed of convergence is determined by the autocovariance function of the DC.
format Preprint
id arxiv_https___arxiv_org_abs_2308_08820
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Diffusion with a broad class of stochastic diffusion coefficients
Uchida, Go
Washizu, Hitoshi
Miyoshi, Hiromi
Statistical Mechanics
Biological Physics
In many physical or biological systems, diffusion can be described by Brownian motions with stochastic diffusion coefficients (DCs). In the present study, we investigate properties of the diffusion with a broad class of stochastic DCs with a novel approach. We show that for a finite time, the propagator is non-Gaussian and heavy-tailed. This means that when the mean square displacements are the same, for a finite time, some of the diffusing particles with stochastic DCs diffuse farther than the particles with deterministic DCs or exhibiting a fractional Brownian motion. We also show that when a stochastic DC is ergodic, the propagator converges to a Gaussian distribution in the long time limit. The speed of convergence is determined by the autocovariance function of the DC.
title Diffusion with a broad class of stochastic diffusion coefficients
topic Statistical Mechanics
Biological Physics
url https://arxiv.org/abs/2308.08820