'Flow & Jam' of frictional athermal systems under shear stress
  We report recent results of molecular dynamics simulations of frictional athermal particles at constant volume fraction and constant applied shear stress, focusing on a range of control parameters where the system first flows, but then jams after a time tjam. On decreasing the volume fraction, the mean jamming time diverges, while its sample fluctuations become so large that the jamming time probability distribution P(tjam) becomes a power-law. We obtain an insight on the origin of this phenomenology focusing on the flowing regime, which is characterized by the presence of a clear correlation between the shear velocity and the mean number of contacts per particles Z, whereby small velocities occur when Z acquires higher values. 
Raffaele Pastore, Massimo Pica Ciamarra and Antonio Coniglio
cond-mat.soft cond-mat.dis-nn cond-mat.mtrl-sci cond-mat.stat-mech