Regensburg 2010 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 6: Poster Session I
DY 6.26: Poster
Montag, 22. März 2010, 16:00–18:00, Poster B2
Diffusive transport of ballistic particles in hard-spheres systems — •Markus Spanner1, Felix Höfling3, Gerd Schröder-Turk1, Klaus Mecke1, and Thomas Franosch2,1 — 1Institut für Theoretische Physik I, Universität Erlangen-Nürnberg, Staudtstr. 7, D-91058 Erlangen, Germany — 2Arnold Sommerfeld Center for Theoretical Physics and CeNS, Department of Physics, Ludwig-Maximilians-Universität München, Theresienstr. 37, D-80333 München, Germany — 3Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom
We study critical diffusive transport in porous media at the percolation threshold by simulating the trajectories of ballistic tracer particles. The porous medium is given by quenched configurations of hard non-overlapping spheres and the size of the tracer particle is adjusted to be the largest possible sphere that can traverse the system in all directions, i.e. the system is at its percolation threshold. Results for the diffusion coefficient at different hard-sphere densities are compared with results for point-like tracers in systems of a Boolean model of uncorrelated overlapping spheres from [1]. Our system of correlated obstacles should represent a more realistic model for porous media than the previous system of uncorrelated spheres. We are interested if sub-diffusive motion in the hard-sphere system still has the same value for the exponent z in δ r2(t) ∝ t−2/z as in the system of overlapping spheres with a point like tracer, because the probability for narrow channels in the system might or might not influence this exponent.
[1] F. Höfling, T. Franosch, E. Frey, Phys.Rev.Lett. 96, 165901(2006)