Non-Gaussian normal diffusion induced by delocalization

Abstract

The non-Gaussian normal diffusion, i.e., the probability distribution function (PDF) is non-Gaussian but the mean squared displacement (MSD) depends on time linearly, has been observed in particle motions. Here we show by numerical simulations that this phenomenon may manifest in energy diffusion along lattices at a non-zero, finite temperature. The model we study is one-dimensional disordered lattices with on-site potential. We find that the energy-density fluctuations are spatially localized if the nonlinear interaction is suppressed, but may relax with a non-Gaussian PDF and a linear time-dependent MSD when the nonlinear interaction is turned on. Our analysis suggests that the mechanism lies in the delocalization properties of the localized modes.

4 pages, 4 figures

References in corpus (4)

• "Diffusing diffusivity": A model for anomalous and "anomalous yet Brownian" diffusion
• Multiple Excitation of Confined Graphene Plasmons by Single Free Electrons
• Effect of phonon-phonon interactions on localization
• Green functions of interacting systems in the strongly localized regime

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• Non-Gaussian Normal Diffusion in a Fluctuating Corrugated Channel
• Quenched trap model on the extreme landscape: the rise of sub-diffusion and non-Gaussian diffusion
• Two-dimensional active motion
• Heat perturbations spreading in the Fermi-Pasta-Ulam-$\beta$ system with next-nearest-neighbor coupling: Competition between phonon dispersion and nonlinearity
• Anomalous interfacial temperature profile induced by phonon localization