title: Rounding of the localization transition in model porous media.
abstract: The generic mechanisms of anomalous transport in porous media are investigated by computer simulations of two-dimensional model systems. In order to bridge the gap between the strongly idealized Lorentz model and realistic models of porous media, two models of increasing complexity are considered: a cherry-pit model with hard-core correlations as well as a soft-potential model. An ideal gas of tracer particles inserted into these structures is found to exhibit anomalous transport which extends up to several decades in time. Also, the self-diffusion of the tracers becomes suppressed upon increasing the density of the systems. These phenomena are attributed to an underlying percolation transition. In the soft potential model the transition is rounded, since each tracer encounters its own critical density according to its energy. Therefore, the rounding of the transition is a generic occurrence in realistic, soft systems.
authors.affiliation: Institut für Theoretische Physik II: Weiche Materie, Heinrich Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany. horbach@thphy.uni-duesseldorf.de.
authors.forename: Simon K
authors.initials: SK
authors.lastname: Schnyder
authors.forename: Markus
authors.initials: M
authors.lastname: Spanner
authors.forename: Felix
authors.initials: F
authors.lastname: Höfling
authors.forename: Thomas
authors.initials: T
authors.lastname: Franosch
authors.forename: Jürgen
authors.initials: J
authors.lastname: Horbach