Critical scaling and heterogeneous superdiffusion across the jamming/rigidity transition of a granular glass

¹  CEA Saclay/SPEC, URA2464 - L'Orme des Merisiers, 91191 Gif-sur-Yvette, France, EU
²  CEA Saclay/SPhT, UMR2306 - L'Orme des Merisiers, 91191 Gif-sur-Yvette, France, EU
³  Science & Finance, Capital Fund Management - 6-8 Bd. Haussmann, 75009 Paris, France, EU

Corresponding author: olivier.dauchot@cea.fr

Received: 10 March 2008
Accepted: 25 June 2008

Abstract

The dynamical properties of a dense horizontally vibrated bidisperse granular monolayer are experimentally investigated. The quench protocol produces states with a frozen structure of the assembly, but the remaining degrees of freedom associated with contact dynamics control the appearance of macroscopic rigidity. We provide decisive experimental evidence that this transition is a critical phenomenon, with increasingly collective and heterogeneous rearrangements occurring at length scales much smaller than the grain diameter, presumably reflecting the contact force network fluctuations. Dynamical correlation time and length scales soar on both sides of the transition, as the volume fraction varies over a remarkably tiny range (). We characterize the motion of individual grains, which becomes super-diffusive at the jamming transition , signaling long-ranged temporal correlations. Correspondingly, the system exhibits long-ranged four-point dynamical correlations in space that obey critical scaling at the transition density.