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This article aims to develop a direct numerical approach to solve the space-fractional partial differential equations (PDEs) based on a new differential quadrature (DQ) technique. The fractional derivatives are approximated by the weighted…

Numerical Analysis · Mathematics 2017-01-24 X. G. Zhu , Y. F. Nie

In this work, we develop variational formulations of Petrov-Galerkin type for one-dimensional fractional boundary value problems involving either a Riemann-Liouville or Caputo derivative of order $\alpha\in(3/2, 2)$ in the leading term and…

Numerical Analysis · Mathematics 2015-12-18 Bangti Jin , Raytcho Lazarov , Zhi Zhou

A model of the thin shell expanding into a uniform ambient medium is developed. Density perturbations are described using equations with linear and quadratic terms, and the linear and the nonlinear solutions are compared. We follow the time…

Astrophysics · Physics 2007-05-23 R. Wunsch , J. Palous

The paper investigates solutions of the fractional hyperbolic diffusion equation in its most general form with two fractional derivatives of distinct orders. The solutions are given as spatial-temporal homogeneous and isotropic random…

Probability · Mathematics 2023-10-09 Nikolai Leonenko , Andriy Olenko , Jayme Vaz

Spherically symmetric solutions in F(R) theories in astronomical systems with rising energy density are studied. The range of parameters is established for which the flat space-time approximation for the background metric is valid. For the…

General Relativity and Quantum Cosmology · Physics 2015-06-16 E. V. Arbuzova , A. D. Dolgov , L. Reverberi

An analytical solution of the perturbed equations is obtained, which exists in all ergodic models of collisionless spherical stellar systems with a single length parameter. This solution corresponds to variations of this parameter, i.e.,…

Astrophysics of Galaxies · Physics 2023-11-10 Evgeny V. Polyachenko , Ilia G. Shukhman

In this paper, the relationships between Lie symmetry groups and fundamental solutions for a class of conformable time fractional partial differential equations (PDEs) with variable coefficients are investigated. Specifically, the…

Analysis of PDEs · Mathematics 2023-05-02 Xiaoyu Cheng , Lizhen Wang

In the realm of complexity, it is argued that adequate modeling of TeV-physics demands an approach based on fractal operators and fractional calculus (FC). Non-local theories and memory effects are connected to complexity and the FC. The…

High Energy Physics - Theory · Physics 2013-06-25 Cresus F. L. Godinho , J. Weberszpil , J. A. Helayël-Neto

In this paper, approximate solutions for a class of fractional Lane - Emden type equations based on the series expansion method are presented. Various examples are introduced and discussed. The recurrence relation for the components of the…

Classical Analysis and ODEs · Mathematics 2020-03-25 M. I. Nouh , Emad A-B. Abdel-Salam

An expansion of a density field or particle distribution in basis functions which solve the Poisson equation both provides an easily parallelized n-body force algorithm and simplifies perturbation theories. The expansion converges quickly…

Astrophysics · Physics 2009-10-30 Martin D. Weinberg

This work studies exact solvability of a class of fractional reaction-diffusion equation with the Riemann-Liouville fractional derivatives on the half-line in terms of the similarity solutions. We derived the conditions for the equation to…

Statistical Mechanics · Physics 2024-03-12 C. -L. Ho

(abridged version) Identifying the processes that determine the initial mass function of stars (IMF) is a fundamental problem in star formation theory. One of the major uncertainties is the exact chemical state of the star forming gas and…

Astrophysics · Physics 2015-11-11 R. S. Klessen , A. -K. Jappsen , R. B. Larson , Y. Li , M. -M. Mac Low

We provide a new class of interior solutions for anisotropic stars admitting conformal motion. The Einstein's field equations in this construction are solved for specific choices of the density/mass functions. We analyze the behavior of the…

General Relativity and Quantum Cosmology · Physics 2010-11-03 Farook Rahaman , Mubasher Jamil , Ranjan Sharma , Kausik Chakraborty

In this paper we study the isotropic cases of static charged fluid spheres in general relativity. For this purpose we consider two different specialization and under these we solve the Einstein-Maxwell field equations in isotropic…

General Relativity and Quantum Cosmology · Physics 2011-08-25 Basanti Das , Pratap Chandra Ray , Irina Radinschi , Farook Rahaman , Saibal Ray

We show the existence of a new class of initially smooth spherically symmetric self-similar solutions to the non-isentropic Euler-Poisson system. These solutions exhibit supersonic gravitational implosion in the sense that the density…

Analysis of PDEs · Mathematics 2025-03-18 Christopher Alexander , Mahir Hadžić , Matthew Schrecker

The ultra-relativistic Euler equations for an ideal gas are described in terms of the pressure $p$, the spatial part $\underline{u} \in \R^3$ of the dimensionless four-velocity and the particle density $n$. Radially symmetric solutions of…

Numerical Analysis · Mathematics 2020-02-05 Matthias Kunik , Hailiang Liu , Gerald Warnecke

We introduce a simplified technique for incorporating diffusive phenomena into lattice-gas molecular dynamics models. In this method, spatial interactions take place one dimension at a time, with a separate fractional timestep devoted to…

Cellular Automata and Lattice Gases · Physics 2007-05-23 Raissa M. D'Souza , Norman H. Margolus , Mark A. Smith

This paper is in continuation of the authors' recently published paper (Journal of Mathematical Physics 55(2014)083519) in which computational solutions of an unified reaction-diffusion equation of distributed order associated with Caputo…

Mathematical Physics · Physics 2016-10-31 R. K. Saxena , A. M. Mathai , H. J. Haubold

Assuming the separable augmented density, it is always possible to construct a distribution function of a spherical population with any given density and anisotropy. We consider under what conditions the distribution constructed as such is…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-19 J. An , E. Van Hese , M. Baes

We present an algorithm to generalize a plethora of well-known solutions to Einstein field equations describing spherically symmetric relativistic fluid spheres by relaxing the pressure isotropy condition on the system. By suitably fixing…

General Physics · Physics 2018-02-14 S. Thirukkanesh , F. C. Ragel , Ranjan Sharma , Shyam Das