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We report on generic relations between fractional flow and pressure in steady two-phase flow in porous media. The main result is a differential equation for fractional flow as a function of phase saturation. We infer this result from two…

Condensed Matter · Physics 2007-05-23 Henning Arendt Knudsen , Alex Hansen

Extensions of Einstein's General Relativity (GR) can formally be given a GR structure in which additional geometric degrees of freedom are mapped on an effective energy-momentum tensor. The corresponding effective cosmic medium can then be…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-11 Winfried Zimdahl , Hermano Velten , William C. Algoner

In the present work, we investigate the potential of fractional derivatives to model atmospheric dispersion of pollutants. We propose simple fractional differential equation models for the steady state spatial distribution of concentration…

Atmospheric and Oceanic Physics · Physics 2017-02-22 A. G. O. Goulart , M. J. Lazo , J. M. S. Suarez , D. M. Moreira

A new method of solving the Einstein-Friedmann dynamical equations of a spatially homogeneous and isotropic universe is presented. The method is applicable when the equation of state of the material content assumes the form P=(g -1) rho, g…

Classical Physics · Physics 2009-10-31 Valerio Faraoni

In this paper, we consider a non-static spherical geometry and formulate its extension for the case of anisotropic matter configuration through minimal gravitational decoupling in $f(\mathbb{R},\mathbb{T})$ theory. We apply a particular…

General Relativity and Quantum Cosmology · Physics 2023-07-12 Tayyab Naseer , M. Sharif

Recent polarized Raman scattering experiments indicate that fractional quantum Hall systems host a chiral spin-2 neutral collective mode, the long-wavelength limit of the magnetoroton, which behaves as a condensed-matter graviton. We…

Strongly Correlated Electrons · Physics 2025-09-05 Yi-Hsien Du

A numerical method to solve the fractional diffusion equation, which could also be easily extended to many other fractional dynamics equations, is considered. These fractional equations have been proposed in order to describe anomalous…

Numerical Analysis · Mathematics 2025-10-20 S. B. Yuste , L. Acedo

In this paper we study anisotropic spherical polytropes within the framework of general relativity. Using the anisotropic Tolman-Oppenheimer-Volkov (TOV) equations, we explore the relativistic anisotropic Lane-Emden equations. We find how…

General Relativity and Quantum Cosmology · Physics 2016-07-20 F. Shojai , M. Kohandel , A. Stepanian

We survay our recent results on fractional gravity theory. It is also provided the Main Theorem on encoding of geometric data (metrics and connections in gravity and geometric mechanics) into solitonic hierarchies. Our approach is based on…

Mathematical Physics · Physics 2012-03-13 Dumitru Baleanu , Sergiu I. Vacaru

This paper develops a fully discrete Fourier spectral Galerkin (FSG) method for the fractional Zakharov--Kuznetsov (fZK) equation posed on a two-dimensional periodic domain. The equation generalizes the classical ZK model by replacing the…

Numerical Analysis · Mathematics 2026-05-29 Mukul Dwivedi , Andreas Rupp

We consider a boundary value problem involving a Riemann-Liouville fractional derivative of order $\alpha\in (3/2,2)$ on the unit interval $(0,1)$. The standard Galerkin finite element approximation converges slowly due to the presence of…

Numerical Analysis · Mathematics 2015-03-02 Bangti Jin , Raytcho Lazarov , Xiliang Lu , Zhi Zhou

We obtain a new anisotropic solution for spherically symmetric spacetimes by analysing of the Karmarkar embedding condition. For this purpose we construct a suitable form of one of the gravitational potentials to obtain a closed form…

General Physics · Physics 2017-06-28 S. K. Maurya , S. D. Maharaj

In this work, we construct a modified version of the Einstein field equations for a vacuum and spherically symmetric spacetime in terms of the Riemann-Louville fractional derivative. The main difference between our approach and other works…

General Relativity and Quantum Cosmology · Physics 2023-05-25 A. Di Teodoro , E. Contreras

We study the gravitational behaviour of a spherically symmetric radiating star when the fluid particles are in geodesic motion. We transform the governing equation into a simpler form which allows for a general analytic treatment. We find…

General Relativity and Quantum Cosmology · Physics 2009-11-13 S. Thirukkanesh , S. D. Maharaj

The problem of constructing flexible stochastic models to describe the variability in shape of solid particles is challenging. Natural objects often exhibit mono- or multi-fractal features, i.e. irregular shapes and self-similar patterns.…

Statistics Theory · Mathematics 2019-01-24 Alfredo Alegría

Starting from the solution of the Einstein field equations in a static and spherically symmetric spacetime which contains an isotropic fluid, we construct a model to represent the interior of compact objects with compactness rate…

General Relativity and Quantum Cosmology · Physics 2023-01-03 Gabino Estevez-Delgado , Joaquin Estevez-Delgado , Modesto Pineda Duran , Arthur Cleary-Balderas

We consider the generalized Forchheimer flows for slightly compressible fluids. Using Muskat's and Ward's general form of Forchheimer equations, we describe the fluid dynamics by a nonlinear degenerate parabolic equation for the density. We…

Numerical Analysis · Mathematics 2015-08-04 Thinh Kieu

In this paper, by using a characterization of functions having fractional derivative, we propose a rigorous fractional Lyapunov function candidate method to analyze stability of fractional-order nonlinear systems. First, we prove an…

Classical Analysis and ODEs · Mathematics 2018-01-16 H. T. Tuan , Hieu Trinh

The notion of fractional dynamics is related to equations of motion with one or a few terms with derivatives of a fractional order. This type of equation appears in the description of chaotic dynamics, wave propagation in fractal media, and…

Classical Physics · Physics 2015-03-19 Vasily E. Tarasov , George M. Zaslavsky

We have solved the Einstein equations of general relativity for a class of metrics with constant spatial curvature and found a non-vanishing Weyl tensor in the presence of an energy-momentum tensor with an anisotropic pressure component.…

General Physics · Physics 2013-09-18 E. Bittencourt , J. M. Salim