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Related papers: Exact EGB models for spherical static perfect flui…

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In the framework of Einstein-scalar-Gauss-Bonnet (EsGB) gravity, we systematically study gravitational waves (GWs), first produced by remote compact astrophysical sources and then propagating through the flat homogeneous and isotropic…

General Relativity and Quantum Cosmology · Physics 2025-03-05 Jared Fier , Henry Han , Bowen Li , Kai Lin , Shinji Mukohyama , Anzhong Wang

Perfect-fluid, static, cylindrically symmetric solutions of Einstein's field equations are obtained for the equations of state $\rho+3p=0$ and $\rho=p$. In the former case, the density and the pressure turn out to be constant while in the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 M. Sharif

A new class of a spatially homogeneous and anisotropic Bianchi type-I cosmological models of the universe for perfect fluid distribution within the framework of scalar-tensor theory of gravitation proposed by Saez and Ballester (Phys. Lett.…

General Physics · Physics 2012-11-15 Anirudh Pradhan , Ajay Kumar Singh , H. Amirhashchi

Exact solutions of a family of Heisenberg-Ising spin-lattice models for a coupled barotropic flow - massive rotating sphere system under microcanonical constraint on relative enstrophy is obtained by the method of spherical constraint.…

Exactly Solvable and Integrable Systems · Physics 2007-05-23 Chjan C. Lim

Due to R. Beig and W. Simon (1990) there is a uniqueness theorem for static solutions of the Einstein-Euler system which applies to fluid models whose equation of state fulfills certain conditions. In this article it is shown that this…

General Relativity and Quantum Cosmology · Physics 2018-07-09 Tomohiro Harada , Maximilian Thaller

In this paper, we study the dynamical irregularity of the locally anisotropic spherical fluids in the context of Einstein-Gauss-Bonnet theory. We aim to describe the causes of energy-density irregularity of self-gravitating fluids and…

General Relativity and Quantum Cosmology · Physics 2025-09-03 Z. Yousaf , Kazuharu Bamba , Mansoor Alshehri , A. Farhat

In this work we study static perfect fluid stars in 2+1 dimensions with an exterior BTZ spacetime. We found the general expression for the metric coefficients as a function of the density and pressure of the fluid. We found the conditions…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Norman Cruz , Marco Olivares , Jose Villanueva

We provide new exact solutions to the Einstein-Maxwell system of equations which are physically reasonable. The spacetime is static and spherically symmetric with a charged matter distribution. We utilise an equation of state which is…

General Relativity and Quantum Cosmology · Physics 2015-06-12 S. D. Maharaj , P. Mafa Takisa

The problem of two stiff fluids (energy density = pressure) moving radially in spherical symmetry is treated. The metric ansatz is chosen spherically symmetric, conformally static with a multiplicative separation of variables. The first…

General Relativity and Quantum Cosmology · Physics 2008-11-05 Valentin Kostov

The instability of non-homoentropic axisymmetric flow of perfect fluid with respect to non-axisymmetric infinitesimal perturbations was investigated by numerical integration of hydrodynamical differential equations in two-dimensional…

Astrophysics · Physics 2009-11-13 V. V. Zhuravlev , N. I. Shakura

We present a new non-diagonal G2 inhomogeneous perfect-fluid solution with barotropic equation of state p=rho and positive density everywhere. It satisfies the global hyperbolicity condition and has no curvature singularity anywhere. This…

General Relativity and Quantum Cosmology · Physics 2010-01-06 Marc Mars

We analyse shear-free spherically symmetric relativistic models of gravitating fluids with heat flow and electric charge defined on higher dimensional manifolds. The solution to the Einstein-Maxwell system is governed by the pressure…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Y. Nyonyi , S. D. Maharaj , K. S. Govinder

The constraints imposed by the relativistic compressibility hypothesis on the square of the speed of sound in a medium are obtained. This result allows to obtain purely hydrodynamic conditions for the physical reality of a perfect energy…

General Relativity and Quantum Cosmology · Physics 2020-04-01 Bartolomé Coll , Joan Josep Ferrando , Juan Antonio Sáez

We study the future stability of cosmological fluids, in spacetimes with an accelerated expansion, which exhibit extreme tilt behavior, ie. their fluid velocity becoming asymptotically null at timelike infinity. It has been predicted in the…

Analysis of PDEs · Mathematics 2024-04-11 Grigorios Fournodavlos , Elliot Marshall , Todd A. Oliynyk

Einstein's field equations for spatially self-similar spherically symmetric perfect-fluid models are investigated. The field equations are rewritten as a first-order system of autonomous differential equations. Dimensionless variables are…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Martin Goliath , Ulf S Nilsson , Claes Uggla

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 study the holographic hydrodynamics in the Einstein-Gauss-Bonnet(EGB) gravity in the framework of the large $D$ expansion. We find that the large $D$ EGB equations can be interpreted as the hydrodynamic equations describing the conformal…

High Energy Physics - Theory · Physics 2019-02-20 Bin Chen , Peng-Cheng Li , Yu Tian , Cheng-Yong Zhang

In this thesis four separate problems in general relativity are considered, divided into two separate themes: coordinate conditions and perfect fluid spheres. Regarding coordinate conditions we present a pedagogical discussion of how the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Petarpa Boonserm

The existence and stability of the Einstein static solution have been built in the Einstein-Cartan gravity. We show that this solution in the presence of perfect fluid with spin density satisfying the Weyssenhoff restriction is cyclically…

General Relativity and Quantum Cosmology · Physics 2014-06-11 K. Atazadeh

An exact solution of the Einstein field equations is found under the assumption of spherically symmetry and the existence of one-parameter group of homothetic motions. This solution has a singularity at $r = 0$, and has non-vanishing…

General Relativity and Quantum Cosmology · Physics 2018-03-23 Ragab M. Gad , M. M. Hassan