The jamming transition of granular media

A statistical mechanical approach to granular material is proposed. Using l attice models from standard statistical mechanics and results from a mean-f ield replica approach we find a jamming transition in granular media closel y related to the glass transition in supercooled liquids. These models repr oduce the logarithmic relaxation in granular compaction and reversible-irre versible lines, in agreement with experimental data. The models also exhibi t aging effects and breakdown of the usual fluctuation-dissipation relation . It is shown that the glass transition may be responsible for the logarith mic relaxation and may be related to the cooperative effects underlying man y phenomena exhibited by granular materials such as the Reynolds transition .