Big Rip and Big Crunch Cosmological Models in a Gravitational Field with Torsion

Bakry, M. A.; Shafeek, A. T.

doi:10.1134/s0202289321010047

Cited by 13 publications

(6 citation statements)

References 55 publications

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“…Torsion can force the worlds of Milne and Einstein-de Sitter to a stage of exponential expansion similar to that of its de Sitter counterpart (Bakry and Shafeek 2021). These examples indicate that a torsion-dominated early universe, or a late, dust-dominated universe with torsion, could go through a phase of accelerated expansion without the need for a cosmological constant, enlargement field, or dark energy.…”

Section: Resultsmentioning

confidence: 99%

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Torsion and shear effect on a Big Rip model in a gravitational field

Bakry

Eid

Khader

2021

Astrophys Space Sci

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In this paper, we investigate the effects of torsion and shears within the framework of the gravitational field with torsion in early and late cosmology. General relativity and torsion field equations are constructed using absolute parallel geometry. The Big Rip model of the Universe has been presented using a special class of Riemann-Cartan geometry and the law of variation of Hubble's parameter. The model does not depend on the curvature constant. The positive condition of the energy density of the matter is satisfied in this model. This cosmological model shows that the torsion and shear effect is strong at the beginning of the Big Bang and at the end of the universe. Through the examination of precise cases of the parameters and initial conditions, we can show that for suitable ranges of the parameters, the dynamic torsion scalar model can exhibit features similar to those of the currently observed accelerating universe. The relationship between the torsion and shear scalars is investigated, and their impact on the accelerating universe is addressed apart from the idea of dark energy.

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Section: Resultsmentioning

confidence: 99%

“…The formulation of the gravitational field with torsion equations (GFT) is given in the following form (Bakry and Shafeek 2021):…”

Section: The Field Equations With Torsionmentioning

confidence: 99%

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Torsion and shear effect on a Big Rip model in a gravitational field

Bakry

Eid

Khader

2021

Astrophys Space Sci

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“…Over the last few decades, astronomical observations and laboratory experiments have revealed several results in fundamental physics, astrophysics, and cosmology which are in conflict with our traditional view of fundamental concepts in physics at different scales, from very small, sub-nuclear scales to very large cosmological scales [1][2][3][4][5][6]. This has led to different theories in quantum gravity (QG) as well as various cosmological models beyond ΛCDM [7][8][9][10][11][12][13][14][15][16][17][18]. At energies close to the Planck energy scale, E P ∼ 1.2 × 10 19 GeV, some of the fundamental concepts in physics such as Lorentz symmetry can be broken as predicted by various QG theories [5,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Investigating the Lorentz invariance violation effect using different cosmological backgrounds

Abdalla,

Cotter,

Backes

et al. 2023

Class. Quantum Grav.

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Familiar concepts in physics, such as Lorentz symmetry, are expected to be broken at energies approaching the Planck energy scale as predicted by several quantum-gravity theories. However, such very large energies are unreachable by current experiments on Earth. Current and future Cherenkov telescope facilities may have the capability to measure the accumulated deformation from Lorentz symmetry for photons traveling over large distances via energy-dependent time delays. One of the best natural laboratories to test Lorentz invariance violation (LIV) signatures are gamma-ray bursts. The calculation of time delays due to the LIV effect depends on the cosmic expansion history. In most of the previous works calculating time lags due to the LIV effect, the standard ΛCDM (or concordance) cosmological model is assumed. In this paper, we investigate whether the LIV signature is significantly different when assuming alternatives to the ΛCDM cosmological model. Specifically, we consider cosmological models with a non-trivial dark-energy equation of state (EoS) (w≠−1), such as the standard Chevallier–Polarski–Linder parameterization, the quadratic parameterization of the dark-energy EoS, and the Pade parameterizations. We find that the relative difference in the predicted time lags is small, of the order of at most a few percent, and thus likely smaller than the systematic errors of possible measurements currently or in the near future.

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“…In the cosmological model, the LR abrupt is a cosmic doomsday, which can be prevented with the quantum effects and the classical evolution of the Universe in f (R) gravity may avoid this doomsday with the DeWitt criterion [23,24]. One can also experience a peculiar model with the big bang behaviour at the first half age of evolution, reaches BR and then with changing behaviour at the end of second half age of the Universe attained the big crunch [25]. Another important result is that, with the present observational value of the deceleration parameter q = −1.08, the present value of the Hubble parameter H 0 for the BR and PR model can respectively be 74.33Kms −1 Mpc −1 and 74.31Kms −1 Mpc −1 [26].…”

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confidence: 99%

Rip cosmological models in extended symmetric teleparallel gravity

Pati,

Kadam,

Tripathy

et al. 2021

Preprint

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In this paper we have investigated some rip cosmological models in an extended symmetric teleparallel gravity theory. We consider the form f (Q, T) = aQ m + bT in the Einstein-Hilbert action and expressed the field equations and the dynamical parameters in terms of the non-metricity Q. Three rip models such as Little Rip, Big Rip and Pseudo Rip are presented. The energy conditions and the cosmographic parameters are derived and analysed for all these models.

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Big Rip and Big Crunch Cosmological Models in a Gravitational Field with Torsion

Cited by 13 publications

References 55 publications

Torsion and shear effect on a Big Rip model in a gravitational field

Torsion and shear effect on a Big Rip model in a gravitational field

Investigating the Lorentz invariance violation effect using different cosmological backgrounds

Rip cosmological models in extended symmetric teleparallel gravity

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