Kantowski-Sachs Universe Models in f(T) Theory of Gravity

Amir, M. Jamil; Yussouf, Muhammad

doi:10.1007/s10773-015-2517-2

Cited by 17 publications

(9 citation statements)

References 38 publications

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“…It is remarked that the signature of the f T coefficient of the Friedmann equation in Refs. [973,49] is incorrect while the sin θ contributions in Ref. [49] should not appear.…”

Section: λCdm Behaviormentioning

confidence: 98%

“…[973,49] is incorrect while the sin θ contributions in Ref. [49] should not appear. Evidently, contrary to the FLRW case, an analytical expression cannot be obtained because J cannot be solely expressed in terms of T .…”

Section: λCdm Behaviormentioning

confidence: 98%

“…The ΛCDM cosmology has been studied in Refs. [973,49] for a perfect isotropic matter fluid with constant EoS w. Here, the cosmology is built on the principle that the average expansion is ΛCDM, meaning it obeys the same evolution equation H 2 = H 0 2 (Ω m0 ã−3 + Ω Λ ). However, since ã and H are now the average quantities, each spatial direction may now evolve differently from one another without each individually exhibiting a behavior similar to the ΛCDM cosmology.…”

Section: λCdm Behaviormentioning

confidence: 99%

See 2 more Smart Citations

Teleparallel Gravity: From Theory to Cosmology

Bahamonde¹,

Dialektopoulos²,

Escamilla-Rivera³

et al. 2021

Preprint

123

259

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Equation of State LHS Left hand side RHS Right hand side STEGR Symmetric teleparallel equivalent of general relativity TEGB Teleparallel equivalent of the Gauss-Bonnet PPN Parameterized post-Newtonian formalism SN Supernova (we use abbreviations SNeIa and SNIa to refer to supernova type 1a) BAO Baryonic Acoustic Oscillations CC Cosmic Chronometers DE Dark energy HDE Holographic Dark Energy QCD Quantum Chromodynamics PlDE Pilgrim Dark Energy CMB Cosmic Microwave Background WMAP Wilkinson Microwave Anisotropy Probe SVT Scalar-Vector-Tensor VLBI Very Long Baseline Interferometry SH0ES Supernova H0 for the Equation of State TRGB Tip of the red-giant branch TDCOSMO Time-delay Cosmography vi

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“…It is remarked that the signature of the f T coefficient of the Friedmann equation in Refs. [973,49] is incorrect while the sin θ contributions in Ref. [49] should not appear.…”

Section: λCdm Behaviormentioning

confidence: 98%

Section: λCdm Behaviormentioning

confidence: 98%

Section: λCdm Behaviormentioning

confidence: 99%

See 1 more Smart Citation

Teleparallel Gravity: From Theory to Cosmology

Bahamonde¹,

Dialektopoulos²,

Escamilla-Rivera³

et al. 2021

Preprint

123

259

View full text Add to dashboard Cite

show abstract

“…We start by considering for simplicity Bianchi type-I and Kantowski-Sachs metrics, thus taking α = 0 in (466). We consider exponential expansion in each spatial direction, namely…”

Section: De Sitter Solutionsmentioning

confidence: 99%

f(T) teleparallel gravity and cosmology

et al. 2016

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Over the past decades, the role of torsion in gravity has been extensively investigated along the main direction of bringing gravity closer to its gauge formulation and incorporating spin in a geometric description. Here we review various torsional constructions, from teleparallel, to Einstein-Cartan, and metric-affine gauge theories, resulting in extending torsional gravity in the paradigm of f (T ) gravity, where f (T ) is an arbitrary function of the torsion scalar. Based on this theory, we further review the corresponding cosmological and astrophysical applications. In particular, we study cosmological solutions arising from f (T ) gravity, both at the background and perturbation levels, in different eras along the cosmic expansion. The f (T ) gravity construction can provide a theoretical interpretation of the late-time universe acceleration, alternative to a cosmological constant, and it can easily accommodate with the regular thermal expanding history including the radiation and cold dark matter dominated phases. Furthermore, if one traces back to very early times, for a certain class of f (T ) models, a sufficiently long period of inflation can be achieved and hence can be investigated by cosmic microwave background observations, or alternatively, the Big Bang singularity can be avoided at even earlier moments due to the appearance of non-singular bounces. Various observational constraints, especially the bounds coming from the large-scale structure data in the case of f (T ) cosmology, as well as the behavior of gravitational waves, are described in detail. Moreover, the spherically symmetric and black hole solutions of the theory are reviewed. Additionally, we discuss various extensions of the f (T ) paradigm. Finally, we consider the relation with other modified gravitational theories, such as those based on curvature, like f (R) gravity, trying to enlighten the subject of which formulation, or combination of formulations, might be more suitable for quantization ventures and cosmological applications. Contents

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“…There exist related works on cosmological analyses in teleparallel f (T ) [25] theory for the anisotropic Kantowski-Sachs universe [53][54][55]. However, they have not used a proper frame for vierbein fields, and their results are invalid since the limit of GR is not recovered in their frame.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic spacetimes in $f(T,B)$ theory II: Kantowski-Sachs Universe

León¹,

Paliathanasis²

2022

Preprint

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In the context of the modified teleparallel f (T, B)-theory of gravity, we consider a homogeneous and anisotropic background geometry described by the Kantowski-Sachs line element. We derive the field equations and investigate the existence of exact solutions. Furthermore, the evolution of the trajectories for the field equations is studied by deriving the stationary points at the finite and infinite regimes. For the f (T, B) = T + F (B) theory, we prove that for a specific limit of the function F (B), the anisotropic Universe has the expanding and isotropic Universe as an attractor with zero spatial curvature. We remark that there are no future attractors where the asymptotic solution describes a Universe with nonzero spatial curvature.

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Kantowski-Sachs Universe Models in f(T) Theory of Gravity

Cited by 17 publications

References 38 publications

Teleparallel Gravity: From Theory to Cosmology

Teleparallel Gravity: From Theory to Cosmology

f(T) teleparallel gravity and cosmology

Anisotropic spacetimes in $f(T,B)$ theory II: Kantowski-Sachs Universe

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