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A fractional diffusion equation with advection term is rigorously derived from a kinetic transport model with a linear turning operator, featuring a fat-tailed equilibrium distribution and a small directional bias due to a given vector…

Analysis of PDEs · Mathematics 2015-10-19 Pedro Aceves-Sanchez , Christian Schmeiser

Mass transport problems are ubiquitous in diverse fields of physics and engineering. With the development of fractional calculus, many have taken to studying problems of fractional mass transport either through numerical simulations or…

Mathematical Physics · Physics 2025-06-18 Nathaniel G. Hermann , M. Shane Hutson

An implicit finite difference method with non-uniform timesteps for solving the fractional diffusion equation in the Caputo form is proposed. The method allows one to build adaptive methods where the size of the timesteps is adjusted to the…

Numerical Analysis · Mathematics 2024-06-28 Santos B. Yuste , Joaquín Quintana-Murillo

In view of the role of reaction equations in physical problems, the authors derive the explicit solution of a fractional reaction equation of general character, that unifies and extends earlier results. Further, an alternative shorter…

Mathematical Physics · Physics 2015-05-18 R. K. Saxena , A. M. Mathai , H. J. Haubold

In this paper we investigate the solution of generalized distributed order diffusion equations with composite time fractional derivative by using the Fourier-Laplace transform method. We represent solutions in terms of infinite series in…

Mathematical Physics · Physics 2017-03-17 Trifce Sandev , Zivorad Tomovski , Bojan Crnkovic

This paper intends on obtaining the explicit solution of $n$-dimensional anomalous diffusion equation in the infinite domain with non-zero initial condition and vanishing condition at infinity. It is shown that this equation can be derived…

Classical Analysis and ODEs · Mathematics 2020-09-23 Durdimurod Durdiev , Elina Shishkina , Sergei Sitnik

We show an application of a subdiffusion equation with Caputo fractional time derivative with respect to another function $g$ to describe subdiffusion in a medium having a structure evolving over time. In this case a continuous transition…

Statistical Mechanics · Physics 2021-07-21 Tadeusz Kosztołowicz , Aldona Dutkiewicz

We consider chains of one-dimensional, piecewise linear, chaotic maps with uniform slope. We study the diffusive behaviour of an initially nonuniform distribution of points as a function of the slope of the map by solving Frobenius-Perron…

chao-dyn · Physics 2009-10-22 R. Klages , J. R. Dorfman

In a series of papers, Saxena, Mathai, and Haubold (2002, 2004a, 2004b) derived solutions of a number of fractional kinetic equations in terms of generalized Mittag-Leffler functions which provide the extension of the work of Haubold and…

Classical Analysis and ODEs · Mathematics 2009-11-11 R. K. Saxena , A. M. Mathai , H. J. Haubold

The problem of anomalous diffusion in the momentum space is considered on the basis of the appropriate probability transition function (PTF). New general equation for description of the diffusion of heavy particles in the gas of the light…

Statistical Mechanics · Physics 2015-05-13 S. A. Trigger

We study a fractional diffusion problem in the divergence form in one space dimension. We define a notion of the viscosity solution. We prove existence of viscosity solutions to the fractional diffusion problem with the Dirichlet boundary…

Analysis of PDEs · Mathematics 2019-05-02 Tokinaga Namba , Piotr Rybka

A version of fractional diffusion on bounded domains, subject to 'homogeneous Dirichlet boundary conditions' is derived from a kinetic transport model with homogeneous inflow boundary conditions. For nonconvex domains, the result differs…

Analysis of PDEs · Mathematics 2016-07-05 Pedro Aceves-Sanchez , Christian Schmeiser

We develop a cut finite element method (CutFEM) for convection-diffusion problems posed on mixed-dimensional domains, i.e., unions of manifolds of different dimensions arranged in a hierarchical structure where lower-dimensional components…

Numerical Analysis · Mathematics 2026-04-09 Erik Burman , Peter Hansbo , Mats G. Larson , Karl Larsson , Shantiram Mahata

A connection between fractional calculus and statistical distribution theory has been established by the authors recently. Some extensions of the results to matrix-variate functions were also considered. In the present article, more results…

Statistical Mechanics · Physics 2011-03-01 A. M. Mathai , H. J. Haubold

The ordinary subdiffusion equation, with a fractional time derivative of at most first order, describes a process in which the propagation velocity of diffusing molecules is unlimited. To avoid this non-physical property different forms of…

Statistical Mechanics · Physics 2025-10-09 Tadeusz Kosztołowicz , Aldona Dutkiewicz , Katarzyna D. Lewandowska

The diffusion in the comb structures is a popular model of geometrically induced anomalous diffusion. In the present work we concentrate on the diffusion along the backbone in a system where sidebranches are planes, and the diffusion…

Statistical Mechanics · Physics 2017-12-13 A. R. Dzhanoev , I. M. Sokolov

We begin with a treatment of the Caputo time-fractional diffusion equation, by using the Laplace transform, to obtain a Volterra intego-differential equation where we may examine the weakly singular nature of this convolution…

Numerical Analysis · Mathematics 2020-01-27 Wesley Davis , Richard Noren , Ke Shi

We study a porous medium equation with fractional potential pressure: $$ \partial_t u= \nabla \cdot (u^{m-1} \nabla p), \quad p=(-\Delta)^{-s}u, $$ for $m>1$, $0<s<1$ and $u(x,t)\ge 0$. To be specific, the problem is posed for $x\in…

Analysis of PDEs · Mathematics 2013-11-28 Diana Stan , Félix del Teso , Juan Luis Vázquez

A framework of finite-velocity model based Boltzmann equation has been developed for convection-diffusion equations. These velocities are kept flexible and adjusted to control numerical diffusion. A flux difference splitting based kinetic…

Numerical Analysis · Mathematics 2024-10-01 S. V. Raghurama Rao , K. S. Shrinath , Ankit Ruhi , Veeredhi Vasudeva Rao

Numerical solutions of stationary diffusion equations on the unit sphere with isotropic lognormal diffusion coefficients are considered. H\"older regularity in $L^p$ sense for isotropic Gaussian random fields is obtained and related to the…

Probability · Mathematics 2023-12-06 Lukas Herrmann , Annika Lang , Christoph Schwab