Barrow holographic dark energy with Granda-Oliveros cut-off

Oliveros, A.; Sabogal, M. A.; Acero, Mario A.

doi:10.48550/arxiv.2203.14464

Cited by 3 publications

(3 citation statements)

References 37 publications

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“…This entropy model has later been considered as a model for holographic dark energy [387,388] (see also Refs. [389][390][391][392][393][394][395][396][397][398][399][400][401][402][403][404][405][406][407][408]). In the toy model considered, a three-dimensional FIG.…”

Section: T Barrow Entropy Modifications To the Schwarzschild Metricmentioning

confidence: 99%

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A$^*$

Vagnozzi¹,

Roy²,

Tsai³

et al. 2022

Preprint

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Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime, allowing us to test whether the Kerr metric provides a good description of the space-time in the vicinity of the event horizons of supermassive BHs. We consider a wide range of well-motivated deviations from classical General Relativity solutions, and constrain them using the Event Horizon Telescope (EHT) observations of Sagittarius A * (SgrA * ), connecting the size of the bright ring of emission to that of the underlying BH shadow and exploiting high-precision measurements of SgrA * 's mass-to-distance ratio. The scenarios we consider, and whose fundamental parameters we constrain, include various regular BH models, string-and non-linear electrodynamics-inspired space-times, scalar field-driven violations of the no-hair theorem, alternative theories of gravity, new ingredients such as the generalized uncertainty principle and Barrow entropy, and BH mimickers including examples of wormholes and naked singularities. We demonstrate that SgrA * 's image places particularly stringent constraints on models predicting a shadow size which is larger than that of a Schwarzschild BH of a given mass: for instance, in the case of Barrow entropy we derive constraints which are significantly tighter than the cosmological ones. Our results are among the first tests of fundamental physics from the shadow of SgrA * and, while the latter appears to be in excellent agreement with the predictions of General Relativity, we have shown that various well-motivated alternative scenarios (including BH mimickers) are far from being ruled out at present.

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Section: T Barrow Entropy Modifications To the Schwarzschild Metricmentioning

confidence: 99%

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A$^*$

Vagnozzi¹,

Roy²,

Tsai³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…The validity and the constraints imposed by the generalized second law of thermodynamics, including the matter-energy content and the horizon entropy, have been investigated in [58]. Additionally, the Barrow holographic DE (BHDE) model was proposed in [59][60][61][62] and has been tested against the latest cosmological data in [63,64]. It was found that BHDE describes very efficiently the late accelerated expansion of the universe, having additionally the correct asymptotic behavior [65].…”

Section: Introductionmentioning

confidence: 99%

Growth of Perturbations in Tsallis and Barrow Cosmology

Farsi¹,

Sheykhi²

2022

Preprint

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We disclose the effects of the entropic corrections to the Friedmann equations on the growth of perturbations in the early stages of the Universe. We consider two types of corrections to the area law of entropy, known as Tsallis and Barrow entropies. Using these corrections to entropy, we derive the modified Friedmann equations and explore the growth of perturbations in a flat universe filled with dark energy (DE) and dark matter (DM). We employ the spherically symmetric collapse formalism and work in the liner regime for the perturbations. We first consider the constant equation of state (EoS) parameter for the DE and then extend our study to the variable EoS parameter for DE. Interstingly enough, we find out that the profile of density contrast quite differs from the standard cosmology. We observe that the growth rate of matter perturbations crucially depend on the values of Tsallis and Barrow parameters. With increasing the correction parameters to the entropy, the total density contrast increases as well. This implies that perturbations grow up faster in a universe with modified entropy corrected Friedmann equations.

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“…The validity and the constraints imposed by the generalized second law of thermodynamics, including the matter-energy content and the horizon entropy, were investigated in [58]. Additionally, the Barrow holographic DE (BHDE) model was proposed in [59][60][61][62] and was tested against the latest cosmological data in [63,64]. It was found that BHDE very efficiently describes the late accelerated expansion of the universe, having additionally the correct asymptotic behavior [65].…”

Section: Introductionmentioning

confidence: 99%

Growth of perturbations in Tsallis and Barrow cosmology

Farsi

Sheykhi

2022

Eur. Phys. J. C

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We report the effects of entropic corrections to the Friedmann equations on the growth of perturbations in the early stages of the universe. We consider two types of corrections to the area law of entropy, known as Tsallis and Barrow entropy. Using these corrections to entropy, we derive the modified Friedmann equations and explore the growth of perturbations in a flat universe filled with dark matter (DM) and the cosmological constant. We employ the spherically symmetric collapse formalism and work in the linear regime for the perturbations. Interestingly enough, we find that the profile of density contrast is quite different from the standard cosmology in Tsallis and Barrow cosmology. We observe that the growth rate of matter perturbations crucially depends on the values of Tsallis and Barrow parameters. By increasing these entropy correction parameters, the total density contrast increases as well. This implies that perturbations grow faster in a universe with modified entropy-corrected Friedmann equations.

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Barrow holographic dark energy with Granda-Oliveros cut-off

Cited by 3 publications

References 37 publications

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A$^*$

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A$^*$

Growth of Perturbations in Tsallis and Barrow Cosmology

Growth of perturbations in Tsallis and Barrow cosmology

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