On Gravitational Entropy of de Sitter Universe

Cosmological approaches of autonomous dynamical system in the framework of f (T ) gravity are investigated in this paper. Our methods applied to flat Friedmann-Robertson-Walker equations in f (T ) gravity, consist to extract dynamical systems whose time-dependence is contained in a single parameter m depending on the Hubble rate of Universe and its second derivative. In our attempt to investigate the autonomous aspect of the dynamical systems reconstructed in both vacuum and nonvacuum f (T ) gravities, two values of the parameter m have been considered for our present analysis. In the so-called quasi-de Sitter inflationary era (m ≃ 0), the corresponding autonomous dynamical systems provide stable de Sitter attractors and unstable de Sitter fixed points. Especially in the vacuum f (T ) gravity, the approximate form of the f (T ) gravity near the stable and the unstable de Sitter fixed points has been performed. The matter dominated era case (m = − 9 2 ) leads to unstable fixed points confirming matter dominated era or not, and stable attractor fixed point describing dark energy dominated era. Another subtlety around the stable fixed point obtained at matter dominated case in the non-vacuum f (T ) gravity is when the dark energy dominated era is reached, at the same time, the radiation perfect fluid dominated succumbs.

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“…is the Lagrangian of the matter field. Then, the variation of this action with respect to tetrad h a µ gives ( [29])…”

Section: Motion Equations In Frw Space-time In the Framework Of F (T ...mentioning

confidence: 99%

Cosmological study of autonomous dynamical systems in modified Tele-Parallel gravity

et al. 2019

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“…We note here that the above expression works as a conservation law for the sum of the energy-momentum tensor of matter fields and the quantity t τ λ . Thus t τ λ is interpreted as the energy-momentum tensor of the gravitational field in the context of f (T ) theories [24],…”

Section: Energy-momentum Complexe (Em C)mentioning

confidence: 99%

“…In order to facilitate the calculation, we rewrite the generalized Landau-Lifshitz energymomentum complex h Lτλ of (24) in term of Teleparallel quantities via the following relation,…”

Section: Energy-momentum Complexe (Em C)mentioning

confidence: 99%

“…Recently, the problem of energy-momentum localization was also considered in modified theories of General Relativity, the so called f (R) theory [21,22] as in Teleparallel gravity [12,13,23] and its modified version namely f (T ) theory [24]. Teleparallel gravity is an alternative description of gravitation which corresponds to a gauge theory for the translation group [25].…”

Section: Introductionmentioning

confidence: 99%

“…The author used the MØller, Einstein, Bergmann-Thomson, and Landau-Lifshitz prescriptions in both GR and Teleparallel gravity to evaluate the energy distribution for the generalized Bianchi-type I metric. For the first time in literature, Ulhoa and Spaniol [24] presented and analyzed an expression for the gravitational energy-momentum vector in the context of f (T ) theories.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

$f(T)$ gravity and energy distribution in Landau-Lifshitz prescription

Ganiou,

Houndjo,

Tossa

2017

Preprint

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We investigate in this paper the Landau-Lifshitz energy distribution in the framework of f (T ) theory view as a modified version of Teleparallel theory. From some important Teleparallel theory results on the localization of energy, our investigations generalize the Landau-Lifshitz prescription from the computation of the energymomentum complex to the framework of f (T ) gravity as it is done in the modified versions of General Relativity. We compute the energy density in the first step for three plane symmetric metrics in vacuum. We find for the second metric that the energy density vanishes independently of f (T ) models. These metrics provide results in perfect agreement with those mentioned in literature. In the second step the calculations are performed for the Cosmic String Spacetime metric. It results that the energy distribution depends on the mass M of cosmic string and it is strongly affected by the parameter of the considered f (T ) quadratic model.

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Deformed special relativity with an invariant minimum speed as an explanation of the cosmological constant

Cruz

2022

Pramana - J Phys

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On Gravitational Entropy of de Sitter Universe

Cited by 6 publications

References 29 publications

Cosmological study of autonomous dynamical systems in modified Tele-Parallel gravity

Cosmological study of autonomous dynamical systems in modified Tele-Parallel gravity

$f(T)$ gravity and energy distribution in Landau-Lifshitz prescription

Deformed special relativity with an invariant minimum speed as an explanation of the cosmological constant

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