Inhomogeneous universe in f(T) theory

Rodrigues, Manuel E.; Daouda, M. Hamani; Houndjo, M. J. S.; Myrzakulov, Ratbay; Sharif, M.

doi:10.1134/s0202289314020108

Cited by 17 publications

(10 citation statements)

References 34 publications

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“…With nondiagonal tetrads, we have both the (anti)evaporation dependence on the parameters of the f(T) model and also the initial horizon perturbation phase. Moreover, our results show the importance of using nondiagonal tetrads where we note that (21) and (22) yield a null second derivative of the algebraic function f(T), (i.e., f TT = 0) while from (49) and (50) one has the freedom to choose the algebraic function f(T) where in general f TT is different from zero. This interesting result comes from the choice of nondiagonal tetrad in this paper.…”

Section: Resultsmentioning

confidence: 92%

“…This solution represents a constant-curvature solution. As we know, different f(T) theory models possess this kind of solution [20]. In f(T) gravity the solution satisfies the analogue condition as T = T 0 , where if we put it in the field equations we obtain the following constraint on the form of f(T):…”

Section: Nariai Solution In F(t)-gravitymentioning

confidence: 97%

“…It is also important to note that for a nonconstant torsion scalar, (21) and (22) lead to the constraint f TT = 0, while from (49) and (50) one has freedom of the choice of the algebraic function, f(T), where in general f TT is different from zero. Further, we mention that the tetrad chosen in this paper is good.…”

Section: Nondiagonal Tetrad Solutionsmentioning

confidence: 99%

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Evaporation phenomena in f(T) gravity

et al. 2015

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We formulate evaporation phenomena in a generic model of generalized teleparallel gravity in Weitzenbock spacetime with diagonal and non-diagonal tetrads basis. We also perform the perturbation analysis around the constant torsion scalar solution named Nariai spacetime which is an exact solution of field equations as the limiting case of the Schwarzschild-de Sitter and in the limit where two back hole and their cosmological horizons coincide. By a carefully analysis of the horizon perturbation equation, we show that (anti)evaporation can not happen if we use a diagonal tetrad basis. This result implies that a typical black hole in any generic form of generalized teleparallel gravity is frozen in its initial state if we use the diagonal tetrads. But in the case of non-diagonal tetrads the analysis is completely different. By a suitable non trivial non-diagonal tetrad basis we investigate the linear stability of the model under perturbations of the metric and torsion simultaneously. We observe that in spite of the diagonal case, both evaporation and anti evaporation can happen. The phenomena depend on the initial phase of the horizon perturbation. In the first mode when we restrict ourselves to the first lower modes the (anti)evaporation happens. So, in non-diagonal case the physical phenomena is reasonable. This is an important advantage of using non-diagonal tetrads instead of the diagonal ones. We also see that this is an universal feature, completely independent from the form of the model.Comment: 16 pages, 2 figure

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Section: Resultsmentioning

confidence: 92%

Section: Nariai Solution In F(t)-gravitymentioning

confidence: 97%

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Evaporation phenomena in f(T) gravity

et al. 2015

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“…Here we have performed the variation of (36) with respect to T, and also have used (34). The solution of (37) is…”

Section: Generality On F(t) Theorymentioning

confidence: 99%

Realistic f(T) model describing the de Sitter epoch of the dark energy dominated universe

et al. 2015

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We consider an exponential model within the so-called f(T) theory of gravity, where T denotes the torsion scalar. We focus our attention on a cosmological feature of a f(T) model, checking whether it may describe the de Sitter stage of the current universe according to the evolution of the redshift, z. Our results show that the model reproduces the de Sitter stage only for low redshifts, where the perturbation function approached zero, whereas the effective parameter of the equation of state goes to -1, which is the expected behavior for any model able to reproduce the de Sitter stage. PACS Nos.: 98.80.-k, 04.50.Kd, 95.36.+x.Résumé : Nous nous penchons sur un modèle exponentiel à l'intérieur de la théorie f(T) de la gravité, où T est la torsion scalaire. Nous focalisons notre effort sur une caractéristique cosmologique du modèle f(T), vérifiant s'il peut décrire la période de de Sitter de notre univers actuel selon l'évolution du déplacement vers le rouge, z. Nos résultats montrent que le modèle reproduit la période de de Sitter seulement pour de faibles déplacements vers le rouge, là où la perturbation tend vers zéro, alors que le paramètre effectif de l'équation d'état tend vers -1, le comportement attendu de tout modèle capable de reproduire la période de de Sitter. [Traduit par la Rédaction]

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“…So there are only solutions with spherical and static symmetry, with the usual tetrads (15), for models with matter described through an anisotropic energy-momentum tensor, where T If the spherically symmetric metric is described by a set of diagonal tetrads with an anisotropic energy-momentum tensor, the symmetry implies that the function f (T ) is linear in T . But when the set of tetrads is non-diagonal, this symmetry can be generalized or broken down when the analytical function f (T ) has nonlinear corrections in T (see the third expression of equation (42) [23]). So in that sense, there is also a no-go theorem to maintain this symmetry in the models of Lemaître-Tolman-Bondi.…”

Section: No-go Theorem For Born-infeld-type and General Charged Smentioning

confidence: 99%

Born-Infeld and charged black holes with non-linear source inf(T) gravity

Ednaldo

Rodrigues

Houndjo

2015

J. Cosmol. Astropart. Phys.

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We investigate f (T ) theory coupled with a nonlinear source of electrodynamics, for a spherically symmetric and static spacetime in 4D. We re-obtain the Born-Infeld and Reissner-Nordstrom-AdS solutions. We generalize the no-go theorem for any content that obeys the relationship T 0 0 = T 1 1 for the energy-momentum tensor and a given set of tetrads. Our results show new classes of solutions where the metrics are related through b(r) = −N a(r). We do the introductory analysis showing that solutions are that of asymptotically flat black holes, with a singularity at the origin of the radial coordinate, covered by a single event horizon. We also reconstruct the action for this class of solutions and obtain the functional form. Using the Lagrangian density of Born-Infeld, we obtain a new class of charged black holes where the action reads f (T ) = −16βBI 1 − 1 + (T /4βBI ) .

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Inhomogeneous universe in f(T) theory

Cited by 17 publications

References 34 publications

Evaporation phenomena in f(T) gravity

Evaporation phenomena in f(T) gravity

Realistic f(T) model describing the de Sitter epoch of the dark energy dominated universe

Born-Infeld and charged black holes with non-linear source inf(T) gravity

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