title: Effective confinement as origin of the equivalence of kinetic temperature and fluctuation-dissipation ratio in a dense shear-driven suspension.
abstract: We study response and velocity autocorrelation functions for a tagged particle in a shear driven suspension governed by underdamped stochastic dynamics. We follow the idea of an effective confinement in dense suspensions and exploit a time scale separation between particle reorganization and vibrational motion. This allows us to approximately derive the fluctuation-dissipation theorem in a "hybrid" form involving the kinetic temperature as an effective temperature and an additive correction term. We show numerically that even in a moderately dense suspension the latter is negligible. We discuss similarities and differences with a simple toy model, a single trapped particle in shear flow.
authors.affiliation: II. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, DE-70550 Stuttgart, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Lander
authors.forename: Udo
authors.initials: U
authors.lastname: Seifert
authors.forename: Thomas
authors.initials: T
authors.lastname: Speck
mesh_terms: D003198:Computer Simulation; D004735:Energy Transfer; D008956:Models, Chemical; D012212:Rheology / Q000379:methods*; D033081:Shear Strength; D013535:Suspensions / Q000737:chemistry*
chemical_list: D013535:Suspensions