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Related papers: Study of polytropes with Generalized polytropic Eq…

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We consider thin spherical shells of matter in both Newtonian gravity and general relativity, and examine their equilibrium configurations and dynamical stability. Thin-shell models are admittedly a poor substitute for realistic stellar…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Philip LeMaitre , Eric Poisson

In this paper we have obtained cosmological models for the static spherically symmetric spacetime with charged anisotropic fluid distribution in (n+2)-dimensions in context of Rosen's Bimetric General Relativity (BGR). An exact solution is…

General Physics · Physics 2017-05-12 A. H. Hasmani , D. N. Pandya

We model a charged anisotropic relativistic star with a quadratic equation of state. Physical features of an exact solution of the Einstein-Maxwell system are studied by incorporating the effect of the nonlinear term from the equation of…

General Relativity and Quantum Cosmology · Physics 2015-06-23 P. Mafa Takisa , S. D. Maharaj , Subharthi Ray

We study a new class of equilibrium two-parametric distribution functions of spherical stellar systems with radially anisotropic velocity distribution of stars. The models are less singular counterparts of the so called generalized…

Astrophysics of Galaxies · Physics 2015-06-16 E. V. Polyachenko , V. L. Polyachenko , I. G. Shukhman

In this paper we developed an analysis of the compressible, isentropic Euler equations in two spatial dimensions for a generalized polytropic gas law. The main focus is rotational flows in the subsonic regimes, described through the…

Analysis of PDEs · Mathematics 2026-04-02 Talita Mello , Wladimir Neves

We revisit the problem of the structure and physical properties of electrically charged static spherically symmetric solutions of the Einstein-Maxwell system of equations where the matter model is a polytropic gas. We consider a…

General Relativity and Quantum Cosmology · Physics 2024-05-03 Andrés Aceña , Bruno Cardin Guntsche , Iván Gentile de Austria

In this paper, we study the polyatomic Boltzmann equation based on continuous internal energy, focusing on physically relevant collision kernels of the hard potentials type with integrable angular part. We establish three main results:…

Analysis of PDEs · Mathematics 2025-10-14 Ricardo Alonso , Milana Čolić

There is introduced a class of barotropic equations of state (EOS) which become polytropic of index $n = 5$ at low pressure. One then studies asymptotically flat solutions of the static Einstein equations coupled to perfect fluids having…

General Relativity and Quantum Cosmology · Physics 2009-10-31 R. Beig , M. Karadi

In this paper, we found new classes of solutions to the Einstein-Maxwell field equations with matter anisotropic distribution incorporating a particular form of electric field intensity within the framework of general relativity. We use a…

General Relativity and Quantum Cosmology · Physics 2023-10-03 Manuel Malaver , Rajan Iyer

A system of equations is developed for a fluid with non-abelian local gauge symmetry. Anisotropy is introduced by requiring that the symmetry breaking preserves a restricted local gauge symmetry about a given direction in the gauge…

Condensed Matter · Physics 2009-09-29 James V. Lindesay , Harry L. Morrison

We make precise the heretofore ambiguous statement that anisotropic stress is a sign of a modification of gravity. We show that in cosmological solutions of very general classes of models extending gravity --- all scalar-tensor theories…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-11 Ippocratis D. Saltas , Ignacy Sawicki , Luca Amendola , Martin Kunz

We show that for any perfect fluid in a static spacetime, if the Einstein constraint equation is satisfied and the temperature of the fluid obeys Tolman's law, then the other components of Einstein's equation are implied by the assumption…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Xiongjun Fang , Sijie Gao

The linear stability of the homogeneous equilibrium of non-relativistic fluids with mass flux and special relativistic fluids with the absolute value of the energy vector as internal energy is investigated. It is proved that the equilibrium…

Nuclear Theory · Physics 2011-07-14 P. Ván

The general properties of a perfect relativistic fluid resulting from the quantum gravitational anomaly are investigated. It is found that, in the limit of a weak gravitational field, this fluid possesses a polytropic equation of state…

High Energy Physics - Theory · Physics 2015-02-09 P. O. Kazinski

In this paper we consider the problem of obtaining a general port-Hamiltonian formulation of Newtonian fluids. We propose the port-Hamiltonian models to describe the energy flux of rotational three-dimensional isentropic and non-isentropic…

Fluid Dynamics · Physics 2020-03-26 Luis A. Mora , Yann Le Gorrec , Denis Matignon , Hector Ramirez , Juan Yuz

We consider static cosmological solutions along with their stability properties in the framework of a recently proposed theory of massive gravity. We show that the modifcation introduced in the cosmological equations leads to several new…

General Relativity and Quantum Cosmology · Physics 2012-07-27 Luca Parisi , Ninfa Radicella , Gaetano Vilasi

We analyze the isothermal property in static fluid spheres within the framework of the modified $f(R, T)$ theory of gravitation. The equation of pressure isotropy of the standard Einstein theory is preserved however, the energy density and…

General Relativity and Quantum Cosmology · Physics 2018-09-26 Sudan Hansraj

Quantum many-body states that frequently appear in physics often obey an entropy scaling law, meaning that an entanglement entropy of a subsystem can be expressed as a sum of terms that scale linearly with its volume and area, plus a…

Quantum Physics · Physics 2021-05-26 Isaac H. Kim

The present status of the shear-free perfect fluid conjecture in general relativity is discussed: I give a review of recent work and present a new formalism which may provide a better understanding of the problems encountered.

General Relativity and Quantum Cosmology · Physics 2025-09-17 Norbert Van den Bergh

We present a class of exact solutions of Einstein's gravitational field equations describing spherically symmetric and static anisotropic stellar type configurations. The solutions are obtained by assuming a particular form of the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 M. K. Mak , T. Harko