title: Space-time correlated two-particle hopping in glassy fluids: structural relaxation, irreversibility, decoupling, and facilitation.
abstract: The microscopic nonlinear Langevin equation (NLE) theory of correlated two-particle dynamics in dense fluids of spherical particles is extended to construct a predictive model of multiple correlated hopping and recaging events of a pair of tagged particles as a function of their initial separation. Modest coarse graining over the liquid structural disorder allows contact to be made with various definitions of irreversible particle motion within the context of a multistate Markov model. The correlated space-time hopping process that underlies structural relaxation can also be analyzed in the context of kinetically constrained models. The dependence of microscopically defined mean persistence and exchange times, their distributions, and relaxation-diffusion decoupling on hard-sphere fluid volume fraction is derived from a model in which irreversible jumps serve as the nucleating persistence event. For a subset of questions, the predictions of the two-particle theory are compared with results from the earlier single-particle NLE approach.
authors.affiliation: Department of Physics, University of Illinois, 1304 W. Green Street, Urbana, Illinois 61801, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Sussman
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Schweizer
mesh_terms: D003198:Computer Simulation; D005898:Glass / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D044367:Phase Transition