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Related papers: Fickian yet non-Gaussian diffusion in two-dimensio…

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Non-Gaussian diffusion is commonly considered as a result of fluctuating diffusivity, which is correlated in time or in space or both. In this work, we investigate the non-Gaussian diffusion in static disordered media via a quenched trap…

Statistical Mechanics · Physics 2018-04-25 Liang Luo , Ming Yi

We use a recently-derived reformulation of the diffusion constant [Stillinger F H and Debenedetti P G 2005 J. Phys. Chem. B 109 6604] to investigate heterogeneous dynamics and non-Gaussian diffusion in a binary Lennard-Jones mixture. Our…

Soft Condensed Matter · Physics 2007-05-23 M. Scott Shell , Pablo G. Debenedetti , Frank H. Stillinger

It was suggested in the literature that the self-diffusion coefficient of simple fluids can be approximated as a ratio of the squared thermal velocity of the atoms to the "fluid Einstein frequency," which can thus serve as a rough estimate…

Soft Condensed Matter · Physics 2018-04-10 Sergey Khrapak , Boris Klumov , Lenaic Couedel

Velocity distributions in a vibrated granular monolayer are investigated experimentally. Non-Gaussian velocity distributions are observed at low vibration amplitudes but cross over smoothly to Gaussian distributions as the amplitude is…

Soft Condensed Matter · Physics 2009-10-31 J. S. Olafsen , J. S. Urbach

The interplay between self-diffusion and excitation lines in space-time was recently studied in kinetically constrained models to explain the breakdown of the Stokes-Einstein law in supercooled liquids. Here, we further examine this…

Statistical Mechanics · Physics 2009-11-10 Ludovic Berthier , David Chandler , Juan P. Garrahan

The passive and active motion of micron-sized tracer particles in crowded liquids and inside living biological cells is ubiquitously characterised by "viscoelastic" anomalous diffusion, in which the increments of the motion feature…

Statistical Mechanics · Physics 2020-05-05 Wei Wang , Flavio Seno , Igor M. Sokolov , Aleksei V. Chechkin , Ralf Metzler

We derive the distribution of particle currents for a system of interacting active Brownian particles in the long time limit using large deviation theory and a weighted many body expansion. We find the distribution is non-Gaussian, except…

Statistical Mechanics · Physics 2018-12-19 Trevor GrandPre , David T. Limmer

The diffusivity of tagged particles is demonstrated to be heterogeneous on time scales comparable to or less than the structural relaxation time %taking place at the interparticle distance in a highly supercooled liquid via 3D molecular…

Soft Condensed Matter · Physics 2009-10-31 Ryoichi Yamamoto , Akira Onuki

Computing analytically the $n$-point density correlations in systems of interacting particles is a long-standing problem of statistical physics, with a broad range of applications, from the interpretation of scattering experiments in simple…

Statistical Mechanics · Physics 2025-07-01 Louison Le Bon , Antoine Carof , Pierre Illien

We propose a practical empirical fitting function to characterize the non-Gaussian displacement distribution functions (DispD) often observed for heterogeneous diffusion problems. We first test this fitting function with the problem of a…

Soft Condensed Matter · Physics 2022-07-20 Le Qiao , Nicholas Ilow , Maxime Ignacio , Gary W. Slater

Simulations are made of a probe particle diffusing through a complex fluid. Probe particle motions are described by the Mori-Zwanzig equation and Mori's orthogonal hierarchy of random forces scheme, subject to the approximation that the…

Soft Condensed Matter · Physics 2014-06-20 George D. J. Phillies

Recently, there has been interest in determining the viscoelastic properties of polymeric liquids and other complex fluids by means of Diffusing Wave Spectroscopy (DWS). In this technique, light-scattering spectroscopy is applied to highly…

Soft Condensed Matter · Physics 2024-08-27 George D. J. Phillies

All prior applications of Diffusing-Wave Spectroscopy (DWS) to aqueous foams rely upon the assumption that the electric field of the detected light is a Gaussian random variable and that, hence, the Siegert relation applies. Here we test…

Soft Condensed Matter · Physics 2009-11-11 A. S. Gittings , D. J. Durian

Experimental work has shown that non-equilibrium concentration fluctuations arise during free diffusion in fluids and theoretical analysis has been carried on. The results show that, in usual three-dimensional fluids, the phenomenon is…

Fluid Dynamics · Physics 2016-08-31 Doriano Brogioli , Alberto Vailati

The effects of a "diffusing diffusivity" (DD), a stochastically time-varying diffusion coefficient, are explored within the frameworks of three different forms of fractional Brownian motion (FBM): (i) the Langevin equation driven by…

Statistical Mechanics · Physics 2025-04-29 Wei Wang , Aleksei V. Chechkin , Ralf Metzler

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…

Disordered Systems and Neural Networks · Physics 2016-04-06 Jianjin Wang , Yong Zhang , Hong Zhao

The linear response description for impurity diffusion in a granular fluid undergoing homogeneous cooling is developed in the preceeding paper. The formally exact Einstein and Green-Kubo expressions for the self-diffusion coefficient are…

Soft Condensed Matter · Physics 2009-11-07 James Lutsko , J. Javier Brey , James W. Dufty

A growing number of biological, soft, and active matter systems are observed to exhibit normal diffusive dynamics with a linear growth of the mean squared displacement, yet with a non-Gaussian distribution of increments. Based on the…

Statistical Mechanics · Physics 2017-04-12 A. V. Chechkin , F. Seno , R. Metzler , I. M. Sokolov

The diffusion of macromolecules in cells and in complex fluids is often found to deviate from simple Fickian diffusion. One explanation offered for this behavior is that molecular crowding renders diffusion anomalous, where the mean-squared…

Soft Condensed Matter · Physics 2016-05-18 Daniel S. Banks , Charmaine Tressler , Robert D. Peters , Felix Höfling , Cécile Fradin

The present work develops a theoretical procedure for obtaining transport coefficients of Yukawa systems from density fluctuations. The dynamics of Yukawa systems are described in the framework of the generalized hydrodynamic model that…

Plasma Physics · Physics 2022-09-14 Ankit Dhaka , PV Subhash , P. Bandyopadhyay , A. Sen