An Isaac Newton Institute Workshop

First-Passage and Extreme Value Problems in Random Processes

Nonequilibrium statistical physics of driven granular gases

30th June 2006

Author: Ben-Naim, E (LANL)

Abstract

Granular systems dissipate kinetic energy and thus, should be driven to maintain a steady-state. In particular, for granular gases, an energy source should balance the dissipation. This talk will review the different steady-states that characterize driven granular gases. When the system is supplied with energy at all scales, as is the case in most of the vigorous driving experiments, the energy input can be modeled using the standard thermal heat bath. The core of the velocity distribution is then close to a Maxwellian but the tail has a stretched exponential form and it is overpopulated with respect to a Maxwellian. When energy is injected at all energy scales, there is an energy cascade from large velocities to small velocities. In this case, the velocity distribution is characterized by a power-law tail.