The nonequilibrium dynamics of a binary Lennard-Jones mixture in a simple shear flow is investigated by means of molecular dynamics simulations. The range of temperature T investigated covers both the liquid, supercooled, and glassy states, while the shear rate #gamma# covers both the linear and nonlinear regimes of rheology. The results can be interpreted in the context of a nonequilibrium, schematic mode-coupling theory developed recently, which makes the theory applicable to a wide range of soft glassy materials. The behavior of the viscosity #eta#(T, #gamma#) is first investigated. In the nonlinear regime, strong shear-thinning is obtained, #eta# approx #gamma#~(-#alpha#(T), with a #alpha#(T) approx = 2/3 in the supercooled regime. Scaling properties of the intermediate scattering functions are studied. Standard "mode-coupling properties" of factorization and time superposition hold in this nonequilibrium situation. The fluctuation-dissipation relation is violated in the shear flow in a way very similar to that predicted theoretically, allowing for the definition of an effective temperature T_eff for the slow modes of the fluid. Temperature and shear rate dependencies of T_eff are studied using density fluctuations as an observable. The observable dependence of T_eff is also investigated. Many different observable are found to lead to the same value of T_eff, suggesting several experimental procedures to access to T_eff. It is proposed that a tracer particle of large mass m_tr may play the role of an "effective thermometer." When the Einstein frequency of the tracers becomes smaller than the inverse relaxation time of the fluid, a nonequilibrium equipartition theorem holds with 展开▼
