https://doi.org/10.1140/epjb/e2005-00360-7
The one-dimensional Lennard-Jones system: collective fluctuations and breakdown of hydrodynamics
Istituto dei Sistemi Complessi e
Istituto Nazionale di Ottica Applicata,
Consiglio Nazionale delle
Ricerche, L.go E. Fermi 6, 50125 Firenze, Italy
Corresponding author: a stefano.lepri@isc.cnr.it
Received:
23
May
2005
Published online:
17
November
2005
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 q2 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.
PACS: 05.60.-k – Transport processes / 66.10.Cb – Diffusion and thermal diffusion
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005
