Effective temperature in athermal systems sheared at fixed normal load.
We perform molecular dynamics simulations of repulsive athermal systems sheared at fixed normal load to study the effective temperature TL defined from time-dependent fluctuation-dissipation relations for density. We show that these systems possess two distinct regimes as a function of the ratio TS/V of the granular temperature to the potential energy per particle. At small TS/V, these systems are pressure controlled and TL is set by the normal load. In contrast, they behave as quasiequilibrium systems with TL approximately TS that increases with the shear rate at large TS/V. These results point out several problems with using TL in thermodynamic descriptions of slowly sheared athermal systems.
Xu
Ning
N
Department of Mechanical Engineering, Yale University, New Haven, Connecticut 06520-8284, USA.
O'Hern
Corey S
CS