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Anomalous sound attenuation in Voronoi liquid.
C Ruscher1, A N Semenov1, J Baschnagel1
1Institut Charles Sadron, CNRS UPR 22, Université de Strasbourg, Strasbourg, France.
The Journal of Chemical Physics
|April 17, 2017
Summary
This study introduces a novel theoretical model for fluids, revealing a violation of universal dynamic structure factor features at low temperatures. The findings challenge conventional understanding of sound attenuation in liquids.
Area of Science:
- * Fluid dynamics
- * Statistical mechanics
- * Condensed matter physics
Background:
- * The hydrodynamic limit of simple fluids and the connection between microscopic and macroscopic scales are well-understood.
- * Universal features of the dynamical structure factor S(k,ω), including its three-peak shape and k-dependence of peak position and width, are established.
- * The k-dependence of S(k,ω) width (∝k²) typically describes sound attenuation rate in liquids.
Purpose of the Study:
- * To present a theoretical model of a monodisperse fluid with interactions defined by Voronoi tessellations (Voronoi liquid).
- * To investigate the low-temperature behavior of this model and identify deviations from universal fluid dynamics.
- * To explain the underlying physical mechanisms responsible for the observed anomalous behavior.
Main Methods:
- * Development of a theoretical model for a fluid based on Voronoi tessellations of configurations.
- * Analysis of the dynamical structure factor S(k,ω) for the proposed Voronoi liquid model.
- * Examination of the low-temperature behavior and sound attenuation rates within the model.
Main Results:
- * The Voronoi liquid model exhibits a marked violation of universal features in S(k,ω) at low temperatures.
- * A significantly reduced sound attenuation rate, proportional to k (∝k), was observed, deviating from the universal ∝k² dependence.
- * This anomalous behavior is linked to a characteristic time scale influencing both viscoelastic relaxational dynamics and momentum diffusion relative to sound propagation.
Conclusions:
- * The Voronoi liquid model demonstrates that deviations from universal fluid dynamics are possible, particularly at low temperatures.
- * The observed anomalous sound attenuation suggests a breakdown of standard hydrodynamic assumptions under specific conditions.
- * The findings highlight the importance of considering viscoelasticity and momentum diffusion timescales in understanding fluid dynamics beyond the conventional hydrodynamic limit.