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DY: Fachverband Dynamik und Statistische Physik

DY 18: Granular matter / contact dynamics

DY 18.4: Vortrag

Mittwoch, 25. März 2009, 17:00–17:15, HÜL 386

Long-Time Tails and Cage Effect in Driven Granular Fluids — •Andrea Fiege¹, 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 the velocity autocorrelation function (VACF) of a driven granular fluid in the stationary state in 3 dimensions with the help of event driven molecular dynamic simulations. As the critical volume fraction of the glass transition in the corresponding elastic fluid is approached, we observe pronounced cage effects in the VACF as well as a strong decrease of the diffusion coefficient, depending on the strength of the inelasticity. At moderate densities the VACF is shown to decay algebraically in time like t^−3/2 if momentum is conserved locally, and like t⁻¹ if momentum is not conserved by the driving. A simple scaling argument supports the observed long-time tails.