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DY: Fachverband Dynamik und Statistische Physik
DY 22: Granular Matter/ Contact Dynamics
DY 22.13: Vortrag
Mittwoch, 16. März 2011, 17:15–17:30, HÜL 186
Tagged particle dynamics close to the glass transition of a driven dissipative system — •Till Kranz1,2, Matthias Sperl3, and Annette Zippelius1,2 — 1Institut für Theoretische Physik, Göttingen — 2MPI für Dynamik und Selbstorganisation, Göttingen — 3Institut für Materialphysik im Weltraum, DLR Köln
In order to reach a steady state, granular (dissipative) systems need an external driving. One of the many possible methods is to fluidize the system by a fluctuating driving force. We have been able recently to establish the existence of a granular glass transition by extending mode coupling theory to nonequilibrium systems [1]. A similar extension of the mode coupling formalism for the incoherent scattering function φs(q,t) of a granular fluid shall be discussed in this contribution. Close to the critical density ϕc(є), that depends on the coefficient of restitution є, the incoherent scattering function φs(q,t) as well as the mean square displacement δ r2(t) are found to exhibit a plateau for intermediate times. Related observables that are also meaningful for the nonequilibrium steady state of a granular fluid are the long time diffusion coefficient D∞ = limt→∞δ r2(t)/t close to the glass transition and the localization length rc at the glass transition. Evidence for a granular glass transition as indicated by the tagged particle dynamics has been found both in experiments and in simulations [2,3]. We will discuss our theoretical findings in relation to the experimental data.
[1] W. T. Kranz, M. Sperl and A. Zippelius, PRL 104, 225701 (2010)
[2] A. R. Abate and D. J. Durian, PRE 74, 031308 (2006)
[3] A. Fiege et al., PRL 102, 098001 (2009)