Spatially heterogenous dynamics in dense, driven granular flowsA. Ferguson and B. Chakraborty
Martin Fisher School of Physics, Brandeis University - Mailstop 057, Waltham, MA 02454-9110, USA
received 18 January 2007; accepted in final form 5 March 2007; published April 2007
published online 29 March 2007
Interest in the dynamical arrest leading to a fluid solid transition in thermal and athermal systems has led to questions about the nature of these transitions. These jamming transitions may be dependent on the influence of extended structures on the dynamics of the system. Here we show results from a simple driven, dissipative, non-equilibrium system which exhibits dynamical heterogeneities similar to those observed in a supercooled liquid which is a system in thermal equilibrium. Observations of the time required for a particular particle to move a distance r reveal the existence of large-scale correlated dynamical regions with characteristic time scales chosen from a broad distribution. The mean squared displacement of ensembles of particles with varying characteristic reveals an intriguing spatially heterogenous mobility. This suggests that a unified framework for jamming will have to be based on the connection between the nature of these heterogeneities and the effective dynamics.
81.05.Rm - Porous materials; granular materials.
45.70.-n - Granular systems.
83.10.Pp - Particle dynamics.
© Europhysics Letters Association 2007