title: Observable dependent quasi-equilibrium in slow dynamics.
abstract: We present examples demonstrating that quasi-equilibrium fluctuation-dissipation behavior at short time differences is not a generic feature of systems with slow nonequilibrium dynamics. We analyze in detail the nonequilibrium fluctuation-dissipation ratio X(t, t(w)) associated with a defect-pair observable in the Glauber-Ising spin chain. It turns out that X not = 1 throughout the short-time regime and in particular X(t(w), t(w)) = 3/4 for t(w) --> infinity. The analysis is extended to observables detecting defects at a finite distance from each other, where similar violations of quasi-equilibrium behavior are found. We discuss our results in the context of metastable states, which suggests that a violation of short-time quasi-equilibrium behavior could occur in general glassy systems for appropriately chosen observables.
authors.affiliation: Department of Mathematics, King's College, Strand, London, WC2R 2LS, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Mayer
authors.forename: Peter
authors.initials: P
authors.lastname: Sollich