## Publications [#303631] of Robert P. Behringer

Papers Published
1. Coulais, C; Behringer, RP; Dauchot, O, Contacts Dynamics Reveals Widom Lines for Jamming, EPL, vol. 100 (February, 2012), pp. 44005 [1202.5687v3], [doi] .

Abstract:
We experimentally study the vicinity of the Jamming transition by investigating the statics and the dynamics of the contact network of an horizontally shaken bi-disperse packing of photo-elastic discs. Compressing the packing very slowly, while maintaining a mechanical excitation, yields a granular glass, namely a frozen structure of vibrating grains. In this glass phase, we observe a remarkable dynamics of the contact network, which exhibits strong dynamical heterogeneities. Such heterogeneities are maximum at a packing fraction $\phi^*$, \emph{distinct} and smaller than the jamming packing fraction $\phi_J$, which is indicated by the abrupt variation of the average number of contact per particle. We demonstrate that the two cross-overs, one for the maximum dynamical heterogeneity, and the other for static jamming, converge at point J in the zero mechanical excitation limit, a behavior reminiscent of the Widom lines in the supercritical phase of a second order critical point. Our findings are discussed in the light of recent numerical and theoretical studies of thermal soft spheres.