title: Velocity autocorrelation function in supercooled liquids: Long-time tails and anomalous shear-wave propagation.
abstract: Molecular dynamic simulations are performed to reveal the long-time behavior of the velocity autocorrelation function (VAF) by utilizing the finite-size effect in a Lennard-Jones binary mixture. Whereas in normal liquids the classical positive t^{-3/2} long-time tail is observed, we find in supercooled liquids a negative tail. It is strongly influenced by the transfer of the transverse current wave across the period boundary. The t^{-5/2} decay of the negative long-time tail is confirmed in the spectrum of VAF. Modeling the long-time transverse current within a generalized Maxwell model, we reproduce the negative long-time tail of the VAF, but with a slower algebraic t^{-2} decay.
authors.affiliation: Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany.|Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: H L
authors.initials: HL
authors.lastname: Peng
authors.affiliation: Peter Grünberg Institut, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: H R
authors.initials: HR
authors.lastname: Schober
authors.affiliation: Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany.|Department of Physics, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
authors.forename: Th
authors.initials: T
authors.lastname: Voigtmann