Berlin 2018 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 82: Glasses and Glass Transition (joint session DY/CPP)
DY 82.7: Talk
Friday, March 16, 2018, 11:45–12:00, BH-N 334
Emergent Many-body Interactions and Inapplicability of Hard Sphere Jamming Theory — •Yoav G. Pollack1, Murari Singh1, Giorgio Parisi2, Corrado Rainone1, and Itamar Procaccia1 — 1Weizmann Institute of Science, Israel — 2Sapienza Universit di Roma, Italy
The mechanism of jamming in soft matter was recently argued to be dimensionally independent by studying the scaling exponents predicted within an infinite-Dimensional mean-field hard-sphere theory. The predicted critical exponents were found to match surprisingly well the numerical measurements in finite-D including 2D and 3D. Such a match seemingly suggests that the infinite-D theory is applicable to realistic systems. Our current work addresses the puzzle of this lack of strong D dependence usually observed in critical phenomena.
We study the jamming transition using effective inter-particle forces. In thermal materials where nevertheless the mean positions are well defined on a given time-scale, these effective forces are what keeps the particles "in place". We observe emergent effective many-body forces, and quantify the non-binary contributions Vs. proximity to jamming. For hard spheres the effective forces are binary precisely at jamming, similarly to the infinite-D limit and propose that this explains the match of theory and measurements. We further conclude that the predictions of infinite-D hard spheres should not be inapplicable to more realistic particles which are never absolutely hard[1].
[1]G. Parisi, Y.G. Pollack, I. Procaccia, C. Rainone and M. Singh, Submitted for publication, arXiv:1709.01607.