Inhomogeneous and anisotropic cosmologies

MacCallum, Malcolm

doi:10.1007/978-94-011-1705-0_11

Cited by 5 publications

(7 citation statements)

References 138 publications

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“…The key point for obtaining this solution lays in the fact that an improper coordinate transformation acting on a static metric could generate a stationary one with nonvanishing angular momentum. This nontrivial effect was shown by Stachel in [27] and the physical interpretation of the parameters of this local transformation was studied in [28]. This procedure, originally established in four dimensions, has been also used in three dimensions [29].…”

Section: Introductionmentioning

confidence: 96%

Rotating hairy black holes in arbitrary dimensions

Erices

Martínez

2018

Phys. Rev. D

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A class of exact rotating black hole solutions of gravity nonminimally coupled to a self-interacting scalar field in arbitrary dimensions is presented. These spacetimes are asymptotically locally anti-de Sitter manifolds and have a Ricci-flat event horizon hiding a curvature singularity at the origin. The scalar field is real and regular everywhere and its effective mass, coming from the nonminimal coupling with the scalar curvature, saturates the Breitenlohner-Freedman bound for the corresponding spacetime dimension. The rotating black hole is obtained by applying an improper coordinate transformation to the static one. Although both spacetimes are locally equivalent, they are globally different, as it is confirmed by the nonvanishing angular momentum of the rotating black hole. It is found that the mass is bounded from below by the angular momentum in agreement with the existence of an event horizon. The thermodynamical analysis is carried out in the grand canonical ensemble. The first law is satisfied and a Smarr formula is exhibited. The thermodynamical local stability of the rotating hairy black holes is established from their Gibbs free energy. However, the global stability analysis establishes that the vacuum spacetime is always preferred over the hairy black hole. Thus, the hairy black hole is likely to decay into the vacuum one for any temperature.

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Section: Introductionmentioning

confidence: 96%

Rotating hairy black holes in arbitrary dimensions

Erices

Martínez

2018

Phys. Rev. D

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“…Parameters c 1 , c 2 , c 3 and c 4 are dimensionless constants and define the coupling between the aether field with gravity. Indeed when constants c Z , Z = 1, 2, 3, 4 vanish then action integral (1) becomes that of the Einstein-Hilbert action.…”

Section: Einstein-aether Gravitymentioning

confidence: 99%

“…By using the dynamical quantities 1 ρ, p and π aeμ ν = π ae e μ ν , kinematic quantities θ and σ and the electric component of the Weyl tensor, E μ ν = Ee μ ν , the gravitational field equations are 1 The set of u μ , e μ ν defines an orthogonal tetrad such that u μ e μ ν = 0; e μ ν e λ μ = δ μ ν + u μ u ν , in order the components of tensors are scalar functions. expressed as a system of first-order algebraic differential equations…”

Section: Dynamical Evolutionmentioning

confidence: 99%

“…Inhomogeneous spacetimes are of special interest in the gravitational theory, because in general they are exact solutions of Einstein's general relativity (GR) without any symmetries. Inhomogeneous cosmological models are those which do not satisfy the cosmological principle, but they provide the limit of Friedmann-Lemaître-Robertson-Walker (FLRW) spacetime [1]. There are many applications of the inhomogeneous spacetimes in cosmological studies which cover all the different epochs of the Universe.…”

Section: Introductionmentioning

confidence: 99%

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Inhomogeneous spacetimes in Einstein-æther cosmology

Paliathanasis¹

2020

Class. Quantum Grav.

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We investigate the existence of inhomogeneous Szekeres spacetimes in Einstein-aether theory. We show that inhomogeneous solutions which can be seen as extension of the Szekeres solutions existing in Einstein-aether gravity only for a specific relation between the dimensionless coefficients which defines the coupling between the aether filed with gravity. The two Szekeres classes of solutions are derived. Also a class of inhomogeneous FLRW-like spacetimes is allowed by the theory for arbitrary values of the dimensionless coefficients of the aether field. The stability of the solutions obtained is performed from where we find that the field equations evolve more variously in Einstein-aether than in General Relativity, where isotropic spacetimes and Kantowski-Sachs spacetimes are found to be attractors.

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“…The study of inhomogeneous and anisotropic cosmologies started soon after the birth of GR [22] and a detailed analysis of exact solutions in terms of the asymptotic of singularities appeared in the works [23,24] followed by numerous attempts [25,26,27,28]. For a more detailed survey on such cosmologies the reader is referred to [29]. The class of Bianchi V spacetimes contains anisotropic and homogeneous cosmologies which are crucial to investigate for several reasons.…”

Section: Physical Interpretation Of New Solutionsmentioning

confidence: 99%

A study of positive energy condition in Bianchi V spacetimes via Noether symmetries

Ali

Hussain

2016

Eur. Phys. J. C

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In this paper we use Noether symmetries of the geodesic Lagrangian in Bianchi V spacetimes to study various cosmological solutions of Einstein's field equations. Our first result is the identification of the subalgebras of Noether symmetries of the equations of motion in such spacetimes with dimension 4, 5, 6, 7, 9 or 10 of the maximal algebra of Lie point symmetries of dimension 13. Second, we give a physical interpretation of new cosmological solutions which satisfy the positive energy condition and yield critical bounds on the expansion coefficient α, in which the underlying nonflat spacetimes have interesting physical properties. Specifically the energy density behaves in one of the following ways. (i) It is positive and constant for all time. (ii) It varies with time and attains a global maximum after some time and then asymptotically converges to zero. (iii) It increases for all time and attains a maximum value at the asymptotic limit t → ∞. In particular a non-flat spacetime is obtained that mimics the expansion in a flat FRW universe dominated by vacuum energy such that the expansion factor has the same form in both. However, the energy density is dynamical in the former.

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Inhomogeneous and anisotropic cosmologies

Cited by 5 publications

References 138 publications

Rotating hairy black holes in arbitrary dimensions

Rotating hairy black holes in arbitrary dimensions

Inhomogeneous spacetimes in Einstein-æther cosmology

A study of positive energy condition in Bianchi V spacetimes via Noether symmetries

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