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We provide new concepts for understanding transport phenomena in flows of granular materials by using a non-Fickian macroscopic model of axial diffusion of a granular material in a finite cylindrical tumbler. The model accounts for…

Soft Condensed Matter · Physics 2023-04-04 Ivan C. Christov , Howard A. Stone

Heterogeneous media diffusion is often described using position-dependent diffusion coefficients and estimated indirectly through mean squared displacement in experiments. This approach may overlook other mechanisms and their interaction…

Statistical Mechanics · Physics 2023-09-11 Haroldo V. Ribeiro , Angel A. Tateishi , Ervin K. Lenzi , Richard L. Magin , Matjaz Perc

Many theoretical and experimental results show that solute transport in heterogeneous porous media exhibits multi-scaling behaviors. To describe such non-Fickian diffusions, this work provides a distributed order Hausdorff diffusion model…

Fluid Dynamics · Physics 2018-12-05 Yingjie Liang , Wen Chen , Wei Xu , HongGuang Sun

The interplay between structure and dynamics in non-equilibrium steady-state is far from understood. We address this interplay by tracking Brownian Dynamics trajectories of particles in a binary colloid of opposite charges in an external…

Soft Condensed Matter · Physics 2016-12-08 Suman Dutta , J. Chakrabarti

Single-file systems, in which particles diffuse in narrow channels while not overtaking each other, is a fundamental model for the tracer subdiffusion observed in confined geometries, such as in zeolites or carbon nanotubes. Twenty years…

Statistical Mechanics · Physics 2024-05-27 Aurélien Grabsch , Olivier Bénichou

We present a numerical simulation study of advective-diffusive scalar transport in three-dimensional high-contrast discontinuous permeability fields, generated with a truncated pluri-Gaussian geostatistical approach. A range of permeability…

Geophysics · Physics 2022-06-16 Eugenio Pescimoro , Matteo Icardi , Giovanni Porta , Marco Bianchi

We study the dynamics of Brownian particles in a heterogeneous one-dimensional medium with a spatially-dependent diffusion coefficient of the form $D(x)\sim |x|^c$, at constant temperature. The particle's probability distribution function…

Statistical Mechanics · Physics 2016-08-03 Shaked Regev , Niels Grønbech-Jensen , Oded Farago

We study the diffusion phenomena on the negatively curved surface made up of congruent heptagons. Unlike the usual two-dimensional plane, this structure makes the boundary increase exponentially with the distance from the center, and hence…

Statistical Mechanics · Physics 2008-07-15 Seung Ki Baek , Su Do Yi , Beom Jun Kim

We consider a one-dimensional diffusion process with coefficients that are periodic outside of a finite 'interface region'. The question investigated in this article is the limiting long time / large scale behaviour of such a process under…

Probability · Mathematics 2010-05-14 Martin Hairer , Charles Manson

Fractional kinetic equations employ non-integer calculus to model anomalous relaxation and diffusion in many systems. While this approach is well explored, it so far failed to describe an important class of transport in disordered systems.…

Statistical Mechanics · Physics 2021-01-04 Wanli Wang , Eli Barkai

A time dependent variational approach is considered to derive the equations of movement for the $\lambda \phi^4$ model. The temporal evolution of the model is performed numerically in the frame of the Gaussian approximation in a lattice of…

High Energy Physics - Phenomenology · Physics 2009-11-07 Fabio L. Braghin

We investigate the dynamics of an overdamped Brownian particle moving in a washboard potential with space dependent friction coefficient. Analytical expressions have been obtained for current and diffusion coefficient. We show that the…

Statistical Mechanics · Physics 2009-11-07 Debasis Dan , A. M. Jayannavar

The problem of mass diffusion in layered systems has relevance to applications in different scientific disciplines, e.g., chemistry, material science, soil science, and biomedical engineering. The mathematical challenge in these type of…

Statistical Mechanics · Physics 2020-10-28 Oded Farago

We study the diffusive dynamics of a Brownian particle in proximity of a flat surface under non-equilibrium conditions, which are created by an anisotropic thermal environment with different temperatures being active along distinct spatial…

Statistical Mechanics · Physics 2017-09-13 Stefano Bo , Ralf Eichhorn

We study concentrated binary colloidal suspensions, a model system which has a glass transition as the volume fraction $\phi$ of particles is increased. We use confocal microscopy to directly observe particle motion within dense samples…

Soft Condensed Matter · Physics 2011-05-20 Takayuki Narumi , Scott V. Franklin , Kenneth W. Desmond , Michio Tokuyama , Eric R. Weeks

Nonlinear stochastic differential equations generating signals with 1/f spectrum have been used so far to describe socio-economical systems. In this paper we consider the motion of a Brownian particle in an inhomogeneous environment such…

Statistical Mechanics · Physics 2015-06-23 Rytis Kazakevicius , Julius Ruseckas

Mathematically modelling diffusive and advective transport of particles in heterogeneous layered media is important to many applications in computational, biological and medical physics. While deterministic continuum models of such…

Computational Physics · Physics 2024-09-16 Elliot J. Carr

Many biological systems regulate phenotypic heterogeneity as a fitness-maximising strategy in uncertain and dynamic environments. Analysis of such strategies is typically confined both to a discrete set of environmental conditions, and to a…

Populations and Evolution · Quantitative Biology 2025-07-02 Alexander P Browning , Sara Hamis

The fractional Fokker-Planck equation for subdiffusion in time-dependent force fields is derived from the underlying continuous time random walk. Its limitations are discussed and it is then applied to the study of subdiffusion under the…

Statistical Mechanics · Physics 2009-06-02 E. Heinsalu , M. Patriarca , I. Goychuk , P. Hanggi

We develop a theory of fluctuations for Brownian systems with weak long-range interactions. For these systems, there exists a critical point separating a homogeneous phase from an inhomogeneous phase. Starting from the stochastic…

Statistical Mechanics · Physics 2009-11-13 Pierre-Henri Chavanis