Cosmological solutions in generalized hybrid metric-Palatini gravity

Rosa, João Luís; Carloni, Sante; Lemos, José P. S.; Lobo, Francisco S. N.

doi:10.1103/physrevd.95.124035

Cited by 70 publications

(36 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(4. 14) In order that the solutions are stable we have to guarantee that the µ − of Eq. (4.14) is greater than µ c , i.e., 2a1(a2+a3+a4) 12a2a3−3a 2 4 > µ c .…”

Section: Stability Regimes: Sufficient Conditions On F (R R)mentioning

confidence: 99%

“…The generalized hybrid metric-Palatini (GHMP) gravity arises as a natural outcome of the hybrid metric-Palatini gravity, where the action R + f (R) is replaced by a general function f (R, R) of both the Ricci and Palatini scalar curvatures [13]. This theory was studied in the context of cosmology, both with dynamical systems methods [13] and with reconstruction techniques [14], for which it was shown, among other behaviors, that exponentially expanding cosmological models exist even when the matter distribution is not purely vacuum. Also, asymptotically anti-de Sitter wormhole solutions with thin shells that satisfy the null energy condition for the whole spacetime were obtained in this theory [15].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stability of Kerr black holes in generalized hybrid metric-Palatini gravity

2020

Self Cite

View full text Add to dashboard Cite

It is shown that the Kerr solution exists in the generalized hybrid metric-Palatini gravity theory and that for certain choices of the function f (R, R) that characterizes the theory, the Kerr solution can be stable against perturbations on the scalar degree of freedom of the theory. We start by verifying which are the most general conditions on the function f (R, R) that allow for the general relativistic Kerr solution to also be a solution of this theory. We perform a scalar perturbation in the trace of the metric tensor, which in turn imposes a perturbation in both the Ricci and Palatini scalar curvatures. To first order in the perturbation, the equations of motion, namely the field equations and the equation that relates the Ricci and the Palatini curvature scalars, can be rewritten in terms of a fourth-order wave equation for the perturbation δR which can be factorized into two secondorder massive wave equations for the same variable. The usual ansatz and separation methods are applied and stability bounds on the effective mass of the Ricci scalar perturbation are obtained. These stability regimes are studied case by case and specific forms of the function f (R, R) that allow for a stable Kerr solution to exist within the perturbation regime studied are obtained.

show abstract

“…(4. 14) In order that the solutions are stable we have to guarantee that the µ − of Eq. (4.14) is greater than µ c , i.e., 2a1(a2+a3+a4) 12a2a3−3a 2 4 > µ c .…”

Section: Stability Regimes: Sufficient Conditions On F (R R)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stability of Kerr black holes in generalized hybrid metric-Palatini gravity

2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Varying the action with respect to the field ϕ and to the field ψ yields after rearrangements, see [34],…”

Section: B Scalar-tensor Representation Of the Generalized Hybrid Mementioning

confidence: 99%

“…One can also find the scalar-tensor representation of this generalized hybrid metric-Palatini gravity, which now has two scalar fields. Exact solutions were constructed representing an FLRW (Friedmann-Lemaître-Robsertson-Walker) universe in a generalized hybrid metric-Palatini theory [34]. Among other relevant results, it was shown that it is possible to obtain exponentially expanding solutions for flat universes even when the cosmology is not purely vacuum.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wormholes in generalized hybrid metric-Palatini gravity obeying the matter null energy condition everywhere

2018

Self Cite

View full text Add to dashboard Cite

Wormhole solutions in a generalized hybrid metric-Palatini matter theory, given by a gravitational Lagrangian f (R, R), where R is the metric Ricci scalar, and R is a Palatini scalar curvature defined in terms of an independent connection, and a matter Lagrangian, are found. The solutions are worked in the scalar-tensor representation of the theory, where the Palatini field is traded for two scalars, ϕ and ψ, and the gravitational term R is maintained. The main interest in the solutions found is that the matter field obeys the null energy condition (NEC) everywhere, including the throat and up to infinity, so that there is no need for exotic matter. The wormhole geometry with its flaring out at the throat is supported by the higher-order curvature terms, or equivalently, by the two fundamental scalar fields, which either way can be interpreted as a gravitational fluid. Thus, in this theory, in building a wormhole, it is possible to exchange the exoticity of matter by the exoticity of the gravitational sector. The specific wormhole displayed, built to obey the matter NEC from the throat to infinity, has three regions, namely, an interior region containing the throat, a thin shell of matter, and a vacuum Schwarzschild anti-de Sitter (AdS) exterior. For hybrid metric-Palatini matter theories this wormhole solution is the first where the NEC for the matter is verified for the entire spacetime keeping the solution under asymptotic control. The existence of this type of solutions is in line with the idea that traversable wormholes bore by additional fundamental gravitational fields, here disguised as scalar fields, can be found without exotic matter. Concomitantly, the somewhat concocted architecture needed to assemble a complete wormhole solution for the whole spacetime may imply that in this class of theories such solutions are scarce. arXiv:1808.08975v1 [gr-qc]

show abstract

Novel Junction Conditions in $$f\left( {\mathcal {G}},~T\right) $$ Modified Gravity

Bhatti

Yousaf

2023

Gen Relativ Gravit

View full text Add to dashboard Cite

Cosmological solutions in generalized hybrid metric-Palatini gravity

Cited by 70 publications

References 70 publications

Stability of Kerr black holes in generalized hybrid metric-Palatini gravity

Stability of Kerr black holes in generalized hybrid metric-Palatini gravity

Wormholes in generalized hybrid metric-Palatini gravity obeying the matter null energy condition everywhere

Novel Junction Conditions in $$f\left( {\mathcal {G}},~T\right) $$ Modified Gravity

Contact Info

Product

Resources

About