The one-dimensional Lennard-Jones system: collective fluctuations and breakdown of hydrodynamics |
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Authors: | Email author" target="_blank">S?LepriEmail author P?Sandri A?Politi |
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Institution: | (1) Istituto dei Sistemi Complessi e Istituto Nazionale di Ottica Applicata, Consiglio Nazionale delle Ricerche, L.go E. Fermi 6, 50125 Firenze, Italy |
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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 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. |
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Keywords: | |
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