Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 15: Statistical Physics far from equilibrium

DY 15.1: Hauptvortrag

Mittwoch, 28. März 2012, 09:30–10:00, MA 004

Fluctuations and State Variables in Driven Granular Materials — •Karen Daniels — Dept. of Physics, North Carolina State University, Raleigh, NC, USA — MPI for Dynamics and Self-Organization, Göttingen

Statistical mechanics has provided a powerful tool for understanding the states of thermodynamic matter, and it is intriguing to investigate whether these successes are also relevant to non-equilibrium systems such as granular materials. I will describe experiments on a two-dimensional dense granular gas of disks suspended on a horizontal air table and agitated at the boundaries. We measure both bulk and particle-scale dynamics, and find a number of thermal-like behaviors including diffusive dynamics, a granular Boyle's law with a van der Waals-like equation of state, and energy equipartition for rotational and translational degrees of freedom. However, the scarcity of free volume provides a crucial control on the dynamics, and each of the above thermal-like behaviors is accompanied by interesting caveats.