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In this work a class of interior solution for Einstein field equations corresponding to a spherically symmetric anisotropic fluid sphere has been obtained under the assumption that the cosmological constant is spatially variable. The…

General Relativity and Quantum Cosmology · Physics 2011-03-07 R. N. Tiwari , Saibal Ray

We consider the Einstein-Maxwell system of equations in the context of isotropic coordinates for matter distributions with anisotropy in the presence of an electric field. We assume a polytropic equation of state for the matter…

General Relativity and Quantum Cosmology · Physics 2015-12-31 Sifiso A. Ngubelanga , Sunil D. Maharaj

We consider the general situation of a compact relativistic body with anisotropic pressures in the presence of the electromagnetic field. The equation of state for the matter distribution is linear and may be applied to strange stars with…

General Relativity and Quantum Cosmology · Physics 2009-01-16 S. Thirukkanesh , S. D. Maharaj

We prove an asymptotic stability result for a linear coupled hyperbolic-elliptic system on a large class of singular background spacetimes in CMC gauge on the n-torus. At each spatial point these background spacetimes are perturbations of…

General Relativity and Quantum Cosmology · Physics 2019-10-21 Ellery Ames , Florian Beyer , James Isenberg

We introduce a new type of generating theorems in General Relativity for anisotropic, static, spherically symmetric solutions of the Einstein field equations. The results are used to derive a class of solutions that can serve as new models…

General Relativity and Quantum Cosmology · Physics 2026-04-14 Paulo Luz , Sante Carloni

We outline the the geometry of locally anisotropic (la) superspaces and la-supergravity. The approach is backgrounded on the method of anholonomic superframes with associated nonlinear connection structure. Following the formalism of…

High Energy Physics - Theory · Physics 2007-05-23 S. I. Vacaru , I. A. Chiosa , Nadejda A. Vicol

In the present paper we analyze and discuss some mathematical aspects of the fluid-static configurations of a self-gravitating perfect gas enclosed in a spherical solid shell. The mathematical model we consider is based on the well-known…

A general formalism to find the density profile of a slowly rotating stellar object in modified gravity is presented. We derive a generic Lane-Emden equation and its analytical solution for a wide class of modified theories of gravity.

General Relativity and Quantum Cosmology · Physics 2022-12-23 Shaswata Chowdhury , Pritam Banerjee , Aneta Wojnar

In this article we perform the Wheeler-DeWitt quantization for Bianchi type $I$ anisotropic cosmological model in the presence of a scalar field minimally coupled to the Einstein-Hilbert gravity theory. We also consider the cosmological…

General Relativity and Quantum Cosmology · Physics 2019-08-14 Saumya Ghosh , Sunandan Gangopadhyay , Prasanta K. Panigrahi

In the context of elasticity theory, rigidity theorems allow to derive global properties of a deformation from local ones. This paper presents a new asymptotic version of rigidity, applicable to elastic bodies with sufficiently stiff…

Analysis of PDEs · Mathematics 2019-09-04 Fabian Christowiak , Carolin Kreisbeck

We have carried out a comprehensive investigation of the quasiparticle properties of a two-dimensional electron gas, interacting via the long-range Coulomb interaction, in the presence of bare mass anisotropy (i.e. with an elliptic…

Mesoscale and Nanoscale Physics · Physics 2021-01-12 Seongjin Ahn , S. Das Sarma

We construct a family of holographic duals to anisotropic states in a strongly coupled gauge theory. On the field theory side the anisotropy is generated by giving a vacuum expectation value to a dimension three operator. We obtain our…

High Energy Physics - Theory · Physics 2020-05-20 Carlos Hoyos , Niko Jokela , José Manuel Penín , Alfonso V. Ramallo

In cosmology an important role is played by homogeneous and isotropic solutions of the Einstein-Euler equations and linearized perturbations of these. This paper proves results on the asymptotic behaviour of scalar perturbations both in the…

Analysis of PDEs · Mathematics 2009-06-16 Paul T. Allen , Alan D. Rendall

We study the structure of static spherical stars made up of a non-relativistic polytropic fluid in linearized higher-curvature theories of gravity (HCG). We first formulate the modified Lane-Emden (LE) equation for the stellar profile…

General Relativity and Quantum Cosmology · Physics 2023-07-26 Shinpei Tonosaki , Tomoya Tachinami , Yuuiti Sendouda

We investigate some new similarity inhomogeneous solutions of anisotropic dark energy and perfect fluid in Bianchi type-I space-time. Three different equation of state parameters along the spatial directions are introduced to quantify the…

General Relativity and Quantum Cosmology · Physics 2018-04-12 Ahmad T Ali , Anil Kumar Yadav , Abdulah K Alzahrani

Recently, the existence of an Amplituhedron for tree level amplitudes in the bi-adjoint scalar field theory has been proved by Arkhani-Hamed et al. We argue that hyperbolic geometry constitutes a natural framework to address the study of…

High Energy Physics - Theory · Physics 2018-09-26 Giulio Salvatori , Sergio Cacciatori

We consider dynamics of a flat anisotropic Universe filled by a perfect fluid near a cosmological singularity in quadratic gravity. Two possible regimes are described -- the Kasner anisotropic solution and an isotropic "vacuum radiation"…

General Relativity and Quantum Cosmology · Physics 2017-01-04 A. Toporensky , D. Müller

This article is the first of two in which we develop a geometric framework for analysing silent and anisotropic big bang singularities. The results of the present article concern the asymptotic behaviour of solutions to linear systems of…

General Relativity and Quantum Cosmology · Physics 2021-10-20 Hans Ringström

We consider the 3D compressible isentropic Euler equations describing the motion of a liquid in an unbounded initial domain with a moving boundary and a fixed flat bottom at finite depth. The liquid is under the influence of gravity and…

Analysis of PDEs · Mathematics 2026-05-08 Chenyun Luo , Junyan Zhang

We investigate newtonian description of accreting compact bodies with hard surfaces, including luminosity and selfgravitation of polytropic perfect fluids. This nonlinear integro-differential problem reduces, under appropriate boundary…

Astrophysics · Physics 2007-05-23 Janusz Karkowski , Edward Malec , Krzysztof Roszkowski