title: Non-Gaussianity and dynamical trapping in locally activated random walks.
abstract: We propose a minimal model of locally activated diffusion, in which the diffusion coefficient of a one-dimensional Brownian particle is modified in a prescribed way-either increased or decreased-upon each crossing of the origin. Such a local mobility decrease arises in the formation of atherosclerotic plaques due to diffusing macrophage cells accumulating lipid particles. We show that spatially localized mobility perturbations have remarkable consequences on diffusion at all scales, such as the emergence of a non-Gaussian multipeaked probability distribution and a dynamical transition to an absorbing static state. In the context of atherosclerosis, this dynamical transition can be viewed as a minimal mechanism that causes macrophages to aggregate in lipid-enriched regions and thereby to the formation of atherosclerotic plaques.
authors.affiliation: Laboratoire de Physique Théorique de la Matière Condensée, CNRS UMR 7600, case courrier 121, Université Paris 6, 4 Place Jussieu, FR-75255 Paris Cedex, France.
authors.forename: O
authors.initials: O
authors.lastname: Bénichou
authors.forename: N
authors.initials: N
authors.lastname: Meunier
authors.forename: S
authors.initials: S
authors.lastname: Redner
authors.forename: R
authors.initials: R
authors.lastname: Voituriez
mesh_terms: D003198:Computer Simulation; D004058:Diffusion; D015233:Models, Statistical; D016011:Normal Distribution