The one-dimensional Lennard-Jones system: collective fluctuations and breakdown of hydrodynamics

Year: 2005

Authors: Politi A., Lepri S., Sandri P.

Autors Affiliation: Istituto dei Sistemi Complessi e Istituto Nazionale di Ottica Applicata, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze, Italy

Abstract: The dynamical correlations of a model consisting of particles constrained on the line and interacting with a nearest-neighbour Lennard-Jones potential are computed by molecular-dynamics simulations. A drastic qualitative change of the spectral shape, from a phonon-like to a diffusive form, is observed upon reducing the particle density even ad moderate temperatures. The latter scenario is due to the spontaneous fragmentation of the crystal-like structure into an ensemble of \”clusters\” colliding among themselves. In both cases, the spectral linewidths do not follow the usual q(2) behaviour for small wavenumbers q, thus signalling a breakdown of linearized hydrodynamics. This anomaly is traced back by the presence of correlations due to the reduced dimensionality.

Journal/Review: EUROPEAN PHYSICAL JOURNAL B

Volume: 47 (4)      Pages from: 549  to: 555

KeyWords: Transport processes; Diffusion and thermal diffusion;
DOI: 10.1140/epjb/e2005-00360-7

Citations: 24
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