Crossing SNe Ia and BAO observational constraints with local ones in hybrid metric-Palatini gravity

Leanizbarrutia, Iker; Lobo, Francisco S. N.; Sáez-Gómez, Diego

doi:10.1103/physrevd.95.084046

Cited by 61 publications

(38 citation statements)

References 61 publications

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“…Particularly, these theories successfully accomplish the result of providing long range scalar mode, able to reproduce dark matter effects [53][54][55], without violating solar system observational constraints and invoking the so-called "chameleon mechanism" [56][57][58]. Furthermore, cosmological solutions have been extensively investigated, obtaining accelerated expansion scenarios [59,60], and studies about compact objects and spherically symmetric static configuration have been performed [61,62]. Here, we deal with a further generalization of these mixed models, and consider a scalar action as in [63,64], where the function f is assumed to depend on both the Ricci scalars, metric and Palatini ones.…”

Section: Introductionmentioning

confidence: 99%

Scalar modes in extended hybrid metric-Palatini gravity: Weak field phenomenology

Bombacigno

Moretti

Montani³

2019

Phys. Rev. D

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We investigate the nature of additional scalar degrees of freedom contained in extended hybrid metric-Palatini gravity, outlining the emergence of two coupled dynamical scalar modes. In particular, we discuss the weak field limit of the theory, both in the static case and from a gravitational waves perspective. In the first case, performing an analysis at the lowest order of the parametrized post-Newtonian structure of the model, we stress the settling of Yukawa corrections to the Newtonian potential. In this respect, we show that one scalar field can have long range interactions and used in the principle for mimicking dark matter effects. Concerning the gravitational waves propagation, instead, we demonstrate that is possible to have well-defined physical degrees of freedom, provided by suitable constraints on model parameters. Moreover, the study of the geodesic deviation points out the presence of breathing and longitudinal polarizations due to these novel scalar waves, which on peculiar assumptions can give rise to beating phenomena during their propagation.

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Section: Introductionmentioning

confidence: 99%

Scalar modes in extended hybrid metric-Palatini gravity: Weak field phenomenology

Bombacigno

Moretti

Montani³

2019

Phys. Rev. D

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“…By using a combination of baryonic acoustic oscillations, supernovae and cosmic microwave background data, the free parameters of the models can be constrained. The analysis was further generalized using a specific HMPG model, given by f (R) ∝ R 2 [39], and the results were compared with the local constraints.…”

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confidence: 99%

Spherically symmetric static vacuum solutions in hybrid metric-Palatini gravity

et al. 2019

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We consider vacuum static spherically symmetric solutions in the hybrid metric-Palatini gravity theory, which is a combination of the metric and Palatini f (R) formalisms unifying local constraints at the Solar System level and the late-time cosmic acceleration. We adopt the scalar-tensor representation of the hybrid metric-Palatini theory, in which the scalar-tensor definition of the potential can be represented as a Clairaut differential equation. Due to their mathematical complexity, it is difficult to find exact solutions of the vacuum field equations, and therefore we adopt a numerical approach in studying the behavior of the metric functions and of the scalar field. After reformulating the field equations in a dimensionless form, and by introducing a suitable independent radial coordinate, the field equations are solved numerically. We detect the formation of a black hole from the presence of Killing horizon for the time-like Killing vector in the metric tensor components. Several models, corresponding to different functional forms of the scalar field potential are considered. The thermodynamic properties of these black hole solutions (horizon temperature, specific heat, entropy and evaporation time due to Hawking luminosity) are also investigated in detail.

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“…It should be said separately that the expression for Shapiro time delay in hybrid f(R)-gravity was obtained in this work for the first time. The restrictions imposed by γ parameter on the parameters of the theory were obtained earlier in the works [6,31].…”

Section: Shapiro Time Delaymentioning

confidence: 99%

On Shapiro time delay in massive scalar-tensor theories

Dyadina,

Labazova

2021

Preprint

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The problem of determining the post-Newtonian parameter γ in massive scalartensor theories is considered. We demonstrate equivalent correspondence between the post-Newtonian parameter γ and the parameter appearing in the equation of null geodysic in massive scalar-tensor theories. We show that massive scalar-tensor theories can be distinguished from general relativity based on the predictions of Shapiro time delay. All calculations are presented using hybrid metric-Palatini f(R)-gravity as an example. The expression for Shapiro time delay in hybrid f(R)-gravity is obtained for the first time.

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Crossing SNe Ia and BAO observational constraints with local ones in hybrid metric-Palatini gravity

Cited by 61 publications

References 61 publications

Scalar modes in extended hybrid metric-Palatini gravity: Weak field phenomenology

Scalar modes in extended hybrid metric-Palatini gravity: Weak field phenomenology

Spherically symmetric static vacuum solutions in hybrid metric-Palatini gravity

On Shapiro time delay in massive scalar-tensor theories

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