Volume 83, Number 4, August 2008
Article Number 46002
Number of page(s) 5
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 04 August 2008
EPL, 83 (2008) 46002
DOI: 10.1209/0295-5075/83/46002

Lower bound on the four-point dynamical susceptibility: Direct experimental test on a granular packing

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 12 December 2007; accepted in final form 25 June 2008; published August 2008
published online 4 August 2008

We track the motion of a horizontally vibrated amorphous assembly of bidisperse hard disks, for densities ranging across the jamming transition. We derive on very general grounds a bound on the dynamical susceptibility in terms of the response of the dynamics to a change in density. This generalizes a similar bound recently derived for equilibrium liquids. We find that in our experimental system the bound is tight and reproduces the non-monotonic behavior of the dynamical susceptibility both in time and density across the jamming transition. The underlying scaling behavior reveals an intimate connection between anomalous diffusion and dynamical heterogeneity.

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

© EPLA 2008