Berlin 2005 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 34: Poster

DY 34.35: Poster

Montag, 7. März 2005, 15:30–18:00, Poster TU D

Hydrodynamic Lyapunov modes in Lennard-Jones fluids: Dynamic Correlations — •Hong-liu Yang and Günter Radons — Theoretische Physik I, Komplexe Systeme und Nichtlineare Dynamik, TU-Chemnitz

Recently we succeeded in identifying hydrodynamic Lyapunov modes (HLMs) also in chaotic many-particle systems with soft core interactions [1,2]. In contrast to the previously studied hard-sphere systems, this became possible only by considering equal-time correlation functions of the coordinate fluctuation density u^{(α )}(x,t) of the Lyapunov vector (LV) associated with the α -th Lyapunov exponent λ ^{(α )}. This approach can be extended to the study of dynamic correlations of u^{(α )}(x,t) [2]. We present detailed results for the corresponding dynamic LV structure factors. They provide us, in addition to the Lyapunov exponent - wave vector dispersion, with the collective dynamic excitations of a given Lyapunov vector. The linear ω -k dispersion relation, which can be extracted from the ”inelastic” peak of a numerical 3-pole approximation of the dynamic LV structure factor, implies that the hydrodynamic Lyapunov modes are propagating. We present results for the density dependence of the corresponding propagation velocities. Results for the k-dependence of the linewidth of the observed central peak are also elaborated.

[1] H.Yang and G. Radons, nlin.CD/0404027

[2] G. Radons and H. Yang, nlin.CD/0404028