Statistical mechanics approach to the jamming transition in granular materials

A system under gravity, made up of hard spheres with an internal degree of freedom, is studied on a 3d lattice under a Monte Carlo tap dynamics. A jamming transition similar to that found in real experiment is found. To understand the nature of such transition a simplified version of the model is also studied in a mean field approximation, using the statistical mechanics approach A la Edwards. A phase transition from a fluid to a glassy phase is found when crystallization is avoided. Interestingly, the nature of such a glassy phase turns out to be the same found in mean field models for glass formers. (C) 2004 Elsevier B.V. All rights reserved.