title: Jamming transition in granular systems.
abstract: Recent simulations have predicted that near jamming for collections of spherical particles, there will be a discontinuous increase in the mean contact number Z at a critical volume fraction phi(c). Above phi(c), Z and the pressure P are predicted to increase as power laws in phi-phi(c). In experiments using photoelastic disks we corroborate a rapid increase in Z at phi(c) and power-law behavior above phi(c) for Z and P. Specifically we find a power-law increase as a function of phi-phi(c) for Z-Z(c) with an exponent beta around 0.5, and for P with an exponent psi around 1.1. These exponents are in good agreement with simulations. We also find reasonable agreement with a recent mean-field theory for frictionless particles.
authors.affiliation: Department of Physics, Duke University, Box 90305, Durham, North Carolina 27708, USA.
authors.forename: T S
authors.initials: TS
authors.lastname: Majmudar
authors.forename: M
authors.initials: M
authors.lastname: Sperl
authors.forename: S
authors.initials: S
authors.lastname: Luding
authors.forename: R P
authors.initials: RP
authors.lastname: Behringer