Cosmic acceleration from second order gauge gravity

Cuzinatto, R. R.; Melo, C. A. M. de; Medeiros, L. G.; Pompeia, P. J.

doi:10.1007/s10509-010-0483-y

Cited by 7 publications

(7 citation statements)

References 49 publications

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“…the equation for a perfect fluid in the standard Friedmann cosmology. On the other hand, a linear perturbative analysis shows that the perturbations in gravitation and matter fields do not grow for the equation of state with ω as given in (51). Therefore, the model proposed here can not describe the structure formation in the early universe.…”

Section: Behaviour Of the F (R ∇R)-model With Timementioning

confidence: 84%

“…In a subsequent work, gravity was interpreted as a second order gauge theory under the Lorentz group, and all possible Lagrangians with linear and quadratic combinations of F and G -or the Riemann tensor, its derivatives and their possible contractions, from the geometrical point of view -were built and classified within that context [50]. In a third paper we selected one of those quadratic Lagrangians for investigating the cosmological consequences of a theory that takes into account R-and (∇R) 2 -terms [51]. That Lagrangian appears in the action S bellow -Eq.…”

Section: Introductionmentioning

confidence: 99%

“…Another improvement we shall do in the present work (when comparing with Ref. [51]) is to use the observational data available to fully test our model. As far as we know, this is the first time this is done for a higher derivative theory of gravity.…”

Section: Introductionmentioning

confidence: 99%

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Observational constraints to a phenomenological $f\left( R,\nabla R\right) $-model

Cuzinatto,

de Melo,

Medeiros

et al. 2013

Preprint

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This paper analyses the cosmological consequences of a modified theory of gravity whose action integral is built from a linear combination of the Ricci scalar R and a quadratic term in the covariant derivative of R. The resulting Friedmann equations are of the fifth-order in the Hubble function. These equations are solved numerically for a flat space section geometry and pressureless matter. The cosmological parameters of the higher-order model are fit using SN Ia data and X-ray gas mass fraction in galaxy clusters. The best-fit present-day t 0 values for the deceleration parameter, jerk and snap are given. The coupling constant β of the model is not univocally determined by the data fit, but partially constrained by it. Density parameter Ω m0 is also determined and shows weak correlation with the other parameters. The model allows for two possible future scenarios: there may be either a premature Big Rip or a Rebouncing event depending on the set of values in the space of parameters. The analysis towards the past performed with the best-fit parameters shows that the model is not able to accommodate a matter-dominated stage required to the formation of structure.

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Section: Behaviour Of the F (R ∇R)-model With Timementioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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Observational constraints to a phenomenological $f\left( R,\nabla R\right) $-model

Cuzinatto,

de Melo,

Medeiros

et al. 2013

Preprint

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“…Some aspects of such a model have been investigated in Refs. [81,82] with respect to the present day acceleration. Rigorously, Eqs.…”

Section: Application: the Starobinsky-podolsky Lagrangianmentioning

confidence: 99%

f(R,∇μ1R,…,∇
Cuzinatto
¹
,
Melo
²
,
Medeiros
³

et al. 2019
Phys. Rev. D
16
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0
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In Cuzinatto et al. [Phys. Rev. D 93, 124034 (2016)], it has been demonstrated that theories of gravity in which the Lagrangian includes terms depending on the scalar curvature R and its derivatives up to order n , i.e. f (R, ∇µR, ∇µ 1 ∇µ 2 R, . . . , ∇µ 1 . . . ∇µ n R) theories of gravity, are equivalent to scalar-multitensorial theories in the Jordan frame. In particular, in the metric and Palatini formalisms, this scalar-multitensorial equivalent scenario shows a structure that resembles that of the Brans-Dicke theories with a kinetic term for the scalar field with ω0 = 0 or ω0 = −3/2, respectively. In the present work, the aforementioned analysis is extended to the Einstein frame. The conformal transformation of the metric characterizing the transformation from Jordan's to Einstein's frame is responsible for decoupling the scalar field from the scalar curvature and also for introducing a usual kinetic term for the scalar field in the metric formalism. In the Palatini approach, this kinetic term is absent in the action. Concerning the other tensorial auxiliary fields, they appear in the theory through a generalized potential. As an example, the analysis of an extension of the Starobinsky model (with an extra term proportional to ∇µR∇ µ R) is performed and the fluid representation for the energy-momentum tensor is considered. In the metric formalism, the presence of the extra term causes the fluid to be an imperfect fluid with a heat flux contribution; on the other hand, in the Palatini formalism the effective energy-momentum tensor for the extended Starobinsky gravity is that of a perfect fluid type. Finally, it is also shown that the extra term in the Palatini formalism represents a dynamical field which is able to generate an inflationary regime without a graceful exit.

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“…The third category of interest here is the one of theories including derivatives of the scalar curvature R [30][31][32][33][34][35][36]. They were inspired by string theory, or motivated by quantum loop corrections, or as alternatives to dark energy models.…”

Section: Introductionmentioning

confidence: 99%

Scalar-multi-tensorial equivalence for higher orderf(R,∇μR,∇μ1
Cuzinatto
¹
,
Melo
²
,
Medeiros
³

et al. 2016
Phys. Rev. D
21
0
7
0
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The equivalence between theories depending on the derivatives of R, i.e. f (R, ∇R, ..., ∇ n R), and scalar-multi-tensorial theories is verified. The analysis is done in both metric and Palatini formalisms. It is shown that f (R, ∇R, ..., ∇ n R) theories are equivalent to scalar-multi-tensorial ones resembling Brans-Dicke theories with kinetic terms ω0 = 0 and ω0 = − 3 2 for metric and Palatini formalisms respectively. This result is analogous to what happens for f (R) theories. It is worthy emphasizing that the scalar-multi-tensorial theories obtained here differ from Brans-Dicke ones due to the presence of multiple tensorial fields absent in the last. Furthermore, sufficient conditions are established for f (R, ∇R, ..., ∇ n R) theories to be written as scalar-multi-tensorial theories. Finally, some examples are studied and the comparison of f (R, ∇R, ..., ∇ n R) theories to f (R, R, ... n R) theories is performed.

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Cosmic acceleration from second order gauge gravity

Cited by 7 publications

References 49 publications

Observational constraints to a phenomenological $f\left( R,\nabla R\right) $-model

Observational constraints to a phenomenological $f\left( R,\nabla R\right) $-model

f(R,∇μ1R,…,∇
Cuzinatto
¹
,
Melo
²
,
Medeiros
³

et al. 2019
Phys. Rev. D
16
0
4
0
View full text Add to dashboard Cite

Scalar-multi-tensorial equivalence for higher orderf(R,∇μR,∇μ1
Cuzinatto
¹
,
Melo
²
,
Medeiros
³

et al. 2016
Phys. Rev. D
21
0
7
0
View full text Add to dashboard Cite

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Cosmic acceleration from second order gauge gravity

Cited by 7 publications

References 49 publications

Observational constraints to a phenomenological $f\left( R,\nabla R\right) $-model

Observational constraints to a phenomenological $f\left( R,\nabla R\right) $-model

f(R,∇μ1R,…,∇Cuzinatto1, Melo2, Medeiros3 et al. 2019Phys. Rev. D16040View full textAdd to dashboardCite

Scalar-multi-tensorial equivalence for higher orderf(R,∇μR,∇μ1Cuzinatto1, Melo2, Medeiros3 et al. 2016Phys. Rev. D21070View full textAdd to dashboardCite

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f(R,∇μ1R,…,∇
Cuzinatto
¹
,
Melo
²
,
Medeiros
³

et al. 2019
Phys. Rev. D
16
0
4
0
View full text Add to dashboard Cite

Scalar-multi-tensorial equivalence for higher orderf(R,∇μR,∇μ1
Cuzinatto
¹
,
Melo
²
,
Medeiros
³

et al. 2016
Phys. Rev. D
21
0
7
0
View full text Add to dashboard Cite