Baryon asymmetry from Barrow entropy: theoretical predictions and observational constraints

Luciano, Giuseppe Gaetano; Saridakis, Emmanuel N.

doi:10.48550/arxiv.2203.12010

Cited by 5 publications

(8 citation statements)

References 73 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

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show abstract

“…In this work, we will argue that δ has to be a function of energy scale and study the implications of Barrow entropy to cosmology (by the expansion of the universe, δ is thus a function of cosmic time). Such a possibility was also raised in [7,10]. We expect that, as quantum gravitational effects become more pronounced near the Big Bang, δ → 1.…”

Section: Introduction: Barrow Entropy and Quantum Gravitymentioning

confidence: 89%

“…( 2), in line with most literature. Cosmological and black hole shadow constraints (assuming a fixed δ) has put an upper bound on δ, which is typically δ O(10 −3 ) or O(10 −4 ) [4][5][6][7][8][9].…”

Section: Introduction: Barrow Entropy and Quantum Gravitymentioning

confidence: 99%

Sign Switching Dark Energy from a Running Barrow Entropy

Di Gennaro,

Ong

2022

Preprint

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“…( 7) are completely different. Cosmological implications of Barrow entropy have been recently studied in the context of Big Bang Nucleosynthesis [51] and Baryogenesis [52], among others. The possibility of a running ∆ has also been considered in [53].…”

Section: Barrow Holographic Dark Energymentioning

confidence: 99%

Inflation and tachyon model of Barrow holographic dark energy

Luciano¹,

Liu²

2022

Preprint

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We study the connection between the tachyon dark energy model and Barrow holographic dark energy (BHDE). The latter is a modified scenario based on the application of the holographic principle with Barrow entropy instead of the usual Bekenstein-Hawking one. We reconstruct the dynamics of the tachyon scalar field both in the presence and absence of interactions between dark energy and matter. For a flat Friedmann-Robertson-Walker Universe, it is shown that the time derivative of the tachyon field Ṫ 2 vanishes. This leads to the condition ωD = −1 for the equation of state parameter of BHDE, providing a potential explanation for the origin of the cosmological constant. On the other hand, the tachyon field exhibits a non-trivial dynamics for a non-flat Universe. In particular, in a closed Universe Ṫ 2 decreases monotonically for increasing cos(R h /a), where R h and a are the future event horizon and the scale factor. The same behavior occurs in an open Universe, but in this case Ṫ 2 < 0, revealing that BHDE cannot model the tachyon dark energy. We then study the inflation mechanism. We find an analytical solution for the characteristic slow-roll parameters, the scalar spectral index and the tensor-to-scalar ratio. We finally comment on the Trans-Planckian Censorship Conjecture in BHDE.

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Baryon asymmetry from Barrow entropy: theoretical predictions and observational constraints

Cited by 5 publications

References 73 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$^*$

Sign Switching Dark Energy from a Running Barrow Entropy

Inflation and tachyon model of Barrow holographic dark energy

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