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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: POSTERS Driven Soft Matter

CPP 20.32: Poster

Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A

Velocity Autocorrelation Function in Driven Granular Gases — •Andrea Fiege¹, Wolf Till Kranz¹, Timo Aspelmeier¹, and Annette Zippelius^1,2 — ¹Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany — ²Institute of Theoretical Physics, University of Göttingen, Germany

We study a system of granular gas particles in 2 and 3 dimensions, i. e. spherical particles which suffer energy loss due to inelastic collisions. An energy source (volume bulk driving) provides a stationary state, allowing us to compute time-delayed correlation functions. Here we concentrate on the velocity autocorrelation function, which is studied with the help of the Mori-Zwanzig projector operator formalism and molecular dynamic simulations. Diffusion coefficients are calculated within the Green-Kubo framework and their enlargement compared to the corresponding Enskog values is shown to exhibit a nonmonotonic dependence on the density. We also discuss the possibility of long time tails in the velocity autocorrelation.