Dresden 2011 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 20: Glasses I (jointly with DF and CPP)

DY 20.7: Vortrag

Mittwoch, 16. März 2011, 11:45–12:00, KÖN Farb

Universal jamming phase diagram in the hard-sphere limit and comparison of the dynamics of soft and hard spheres — •Michael Schmiedeberg¹, Thomas K. Haxton², Sidney R. Nagel³, and Andrea J. Liu⁴ — ¹Institut für Theoretische Physik 2: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany — ²Theory of Nanostructured Materials, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA — ³The James Franck Institute, The University of Chicago, Chicago, IL 60637, USA — ⁴Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA

We present a new formulation of the jamming phase diagram for a class of glass-forming fuids consisting of spheres interacting via finite-ranged repulsions. Our phase diagram is universal at low pressure, i.e. observables such as the relaxation time are insensitive to details of the interaction potential and collapse onto the values for hard spheres.

Furthermore, we show that the dynamics of soft spheres can be described in terms of the dynamics of hard spheres. By introducing an effective hard sphere diameter that is determined from the soft-sphere pair potential via the Andersen-Weeks-Chandler approximation, the relaxation times of soft spheres can be mapped onto the curve known for hard-sphere liquids. These results indicate that the dynamics of soft spheres depend on an effective free volume in a universal way.