paper

Crossover in the Slow Decay of Dynamic Correlations in the Lorentz Model

arXiv:cond-mat/0701659 · doi:10.1103/PhysRevLett.98.140601

Abstract

The long-time behavior of transport coefficients in a model for spatially heterogeneous media in two and three dimensions is investigated by Molecular Dynamics simulations. The behavior of the velocity auto-correlation function is rationalized in terms of a competition of the critical relaxation due to the underlying percolation transition and the hydrodynamic power-law anomalies. In two dimensions and in the absence of a diffusive mode, another power law anomaly due to trapping is found with an exponent -3 instead of -2. Further, the logarithmic divergence of the Burnett coefficient is corroborated in the dilute limit; at finite density, however, it is dominated by stronger divergences.

arXiv commentFull-length paragraph added that exemplifies the relevance for dense fluids and makes a connection to recently observed, novel long-time tails in a hard-sphere fluid

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