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We construct spherically symmetric solutions to the Einstein-Euler equations, which give models of gaseous stars in the framework of the general theory of relativity. We assume a realistic barotropic equation of state. Equilibria of the…

Analysis of PDEs · Mathematics 2016-06-08 Tetu Makino

An AH (affine hypersurface) structure is a pair comprising a projective equivalence class of torsion-free connections and a conformal structure satisfying a compatibility condition which is automatic in two dimensions. They generalize Weyl…

Differential Geometry · Mathematics 2013-06-27 Daniel J. F. Fox

We construct the first eleven-dimensional supergravity solutions, which are regular, have no smearing and possess only SO(2,4) x SO(3) x U(1)_R isometry. They are dual to four-dimensional field theories with N = 2 superconformal symmetry.…

High Energy Physics - Theory · Physics 2013-11-06 P. Marios Petropoulos , Konstadinos Sfetsos , Konstadinos Siampos

Exact solutions of the Einstein's field equations describing a spherically symmetric cosmological model without a big bang or any other kind of singularity recently obtained by Dadhich and Patel (2000) are revisited. The matter content of…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Anirudh Pradhan , Kashika Srivastava , Amrit Lal Ahuja

An exact class of solutions of the 5D vacuum Einstein field equations (EFEs) is obtained. The metric coefficients are found to be non-separable functions of time and the extra coordinate $l$ and the induced metric on $l$ = constant…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Takao Fukui , Sanjeev S. Seahra , Paul S. Wesson

We investigate self-similar scalar field solutions to the Einstein equations in whole cylinder symmetry. Imposing self-similarity on the spacetime gives rise to a set of single variable functions describing the metric. Furthermore, it is…

General Relativity and Quantum Cosmology · Physics 2013-10-07 Eoin Condron , Brien C. Nolan

We show that there exist smooth, simply connected, four-dimensional spin manifolds which do not admit Einstein metrics, but nonetheless satisfy the strict Hitchin-Thorpe inequality. Our construction makes use of the Bauer/Furuta cohomotopy…

Differential Geometry · Mathematics 2007-05-23 Masashi Ishida , Claude LeBrun

The asymptotic properties of conformally static metrics in Einstein-aether theory with a perfect fluid source and a scalar field are analyzed. In case of perfect fluid, some relativistic solutions are recovered such as: Minkowski spacetime,…

General Relativity and Quantum Cosmology · Physics 2021-01-11 Genly Leon , Alfredo Millano , Joey Latta

Solutions to vacuum Einstein field equations with cosmological constant, such as the de Sitter space and the anti-de Sitter space, are basic in different cosmological and theoretical developments. It is also well known that complex…

High Energy Physics - Theory · Physics 2022-03-23 Carlos G. Boiza , Jose A. R. Cembranos

We obtain infinite classes of new Einstein-Sasaki metrics on complete and non-singular manifolds. They arise, after Euclideanisation, from BPS limits of the rotating Kerr-de Sitter black hole metrics. The new Einstein-Sasaki spaces…

High Energy Physics - Theory · Physics 2009-09-17 M. Cvetic , H. Lu , Don N. Page , C. N. Pope

We consider sphere bundles P and P' of totally null planes of maximal dimension and opposite self-duality over a 4-dimensional manifold equipped with a Weyl or Riemannian geometry. The fibre product PP' of P and P' is found to be…

dg-ga · Mathematics 2009-10-28 P. Nurowski

Following a solution generating technique introduced recently by one of us, we transform the Einstein static Universe into a two - fold infinity class of physically acceptable exact perfect fluid solutions of Einstein's equations. Whereas…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Cédric Grenon , Pascal J. Elahi , Kayll Lake

Any $6$-dimensional strict nearly K\"ahler manifold is Einstein with positive scalar curvature. We compute the coindex of the metric with respect to the Einstein-Hilbert functional on each of the compact homogeneous examples. Moreover, we…

Differential Geometry · Mathematics 2022-08-25 Paul Schwahn

Among a family of 2-parameter left invariant metrics on Sp(2), we determine which have nonnegative sectional curvatures and which are Einstein. On the quotiente $\widetilde{N}^{11}=(Sp(2)\times S^4)/S^3$, we construct a homogeneous…

Differential Geometry · Mathematics 2020-04-29 Chao Qian , Zizhou Tang , Wenjiao Yan

A discussion is given of the conformal Einstein field equations coupled with matter whose energy-momentum tensor is trace-free. These resulting equations are expressed in terms of a generic Weyl connection. The article shows how in the…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Christian Lübbe , Juan Antonio Valiente Kroon

The volumes, spectra and geodesics of a recently constructed infinite family of five-dimensional inhomogeneous Einstein metrics on the two $S^3$ bundles over $S^2$ are examined. The metrics are in general of cohomogeneity one but they…

High Energy Physics - Theory · Physics 2009-10-07 Gary W. Gibbons , Sean A. Hartnoll , Yukinori Yasui

We discuss smooth metric measure spaces admitting two weighted Einstein representatives of the same weighted conformal class. First, we describe the local geometries of such manifolds in terms of certain Einstein and quasi-Einstein warped…

Differential Geometry · Mathematics 2025-04-11 Miguel Brozos-Vázquez , Eduardo García-Río , Diego Mojón-Álvarez

We provide an affirmative answer to a question posed by Tod \cite{Tod:1995b}, and construct all four-dimensional Kahler metrics with vanishing scalar curvature which are invariant under the conformal action of Bianchi V group. The…

General Relativity and Quantum Cosmology · Physics 2011-05-09 Maciej Dunajski , Prim Plansangkate

In this new version, we give an affirmative solution to a conjecture of Cheng proposed in 1979 which asserts that the Bergman metric of a smoothly bounded strongly pseudoconvex domain in $\mathbb{C}^n, n\geq 2,$ is K\"ahler-Einstein if and…

Complex Variables · Mathematics 2019-07-18 Xiaojun Huang , Ming Xiao

The Tolman~VII solution, an exact analytic solution to the spherically symmetric, static Einstein equations with a perfect fluid source, has many characteristics that make it interesting for modelling high density physical astronomical…

General Relativity and Quantum Cosmology · Physics 2016-01-26 Ambrish M. Raghoonundun , David W. Hobill