| A microscopic, single-particle kinetic description of glassy dynamics is developed that combines and extends elements of idealized mode coupling theory, density functional theory, and activated rate theory. Thermal fluctuations are included via a random force that destroys the idealized glass transition and restores ergodicity through activated barrier hopping. The approach is predictive and contains no postulated dynamic or thermodynamic divergences.;Application to hard sphere colloidal suspensions yields good, no adjustable parameter agreement with experiment. Connections are predicted between short time dynamics in the nearly localized state, long time relaxation by entropic barrier crossing, and thermodynamics. Dynamic heterogeneity is incorporated due to local barrier fluctuations among (quasi-)static domains resulting from mesoscopic density fluctuations. The common origin of the fluctuation effects is the heterogeneity-induced component of the barrier, which has a volume fraction dependence nearly identical to that of the mean field component. A second form of heterogeneity is due to thermal mobility fluctuations. Single particle Brownian dynamics simulation methods are employed to solve the nonlinear stochastic Langevin equation and establish its full trajectory-level consequences. Predictions are made in qualitative and semiquantitative agreement with experiments and simulations.;The theory is extended to polymer melts based on a coarse-grained model in which the melt is treated as a liquid of segments. The barrier is predicted to be a function of a single parameter that is chemical structure, temperature and pressure dependent. Qualitative agreement with experiment is found for characteristics of the kinetic glass transition, and the importance of the experimentally observed near-universality of the dynamic crossover time is established. |
