Volume 83, Number 4, August 2008
Article Number 46003
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 04 August 2008
EPL, 83 (2008) 46003
DOI: 10.1209/0295-5075/83/46003

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

F. Lechenault1, O. Dauchot1, G. Biroli2 and J. P. Bouchaud3

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

received 10 March 2008; accepted in final form 25 June 2008; published August 2008
published online 4 August 2008

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 ( $\delta \phi /\phi \sim 10^{- 3}$). We characterize the motion of individual grains, which becomes super-diffusive at the jamming transition $\phi _{J}$, 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.

64.70.P- - Glass transitions of specific systems.
05.40.Ca - Noise.
45.70.Cc - Static sandpiles; granular compaction.

© EPLA 2008