Tidal forces in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>f</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mi>R</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math>theories of gravity

Cruz-Dombriz, Álvaro de la; Dunsby, Peter K. S.; Busti, V. C.; Kandhai, Sulona

doi:10.1103/physrevd.89.064029

Cited by 16 publications

(13 citation statements)

References 100 publications

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“…2 with the corresponding diagrams of the ΛCDM model in Refs. [59,70] illustrates that the general behavior of the null geodesic deviation and the observer area-distance in the particular minimal coupling model are almost similar to the ΛCDM model. Hence, this model can remain phenomenologically viable and being tested with the observational data.…”

Section: Gde For Null Vector Fieldsmentioning

confidence: 75%

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Cosmic acceleration from matter–curvature coupling

Zaregonbadi

Farhoudi

2016

Gen Relativ Gravit

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We consider f (R, T ) modified theory of gravity in which, in general, the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar and the trace of the energy-momentum tensor. We indicate that in this type of the theory, the coupling energy-momentum tensor is not conserved. However, we mainly focus on a particular model that matter is minimally coupled to the geometry in the metric formalism and wherein, its coupling energy-momentum tensor is also conserved. We obtain the corresponding Raychaudhuri dynamical equation that presents the evolution of the kinematic quantities. Then for the chosen model, we derive the behavior of the deceleration parameter, and show that the coupling term can lead to an acceleration phase after the matter dominated phase. On the other hand, the curvature of the universe corresponds with the deviation from parallelism in the geodesic motion. Thus, we also scrutinize the motion of the free test particles on their geodesics, and derive the geodesic deviation equation in this modified theory to study the accelerating universe within the spatially flat FLRW background. Actually, this equation gives the relative accelerations of adjacent particles as a measurable physical quantity, and provides an elegant tool to investigate the timelike and the null structures of spacetime geometries. Then, through the null deviation vector, we find the observer area-distance as a function of the redshift for the chosen model, and compare the results with the corresponding results obtained in the literature.

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Section: Gde For Null Vector Fieldsmentioning

confidence: 75%

“…Then in the same section, we attain the results for the ΛCDM model and the particular minimal coupling model, and compare them with each other and also with the corresponding results of the Hu-Sawicki models [72] of f (R) theories obtained in Ref. [70] and f (T ) gravity attained in Ref. [71].…”

Section: Introductionmentioning

confidence: 75%

Cosmic acceleration from matter–curvature coupling

Zaregonbadi

Farhoudi

2016

Gen Relativ Gravit

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“…In this short remark, we clarify the difference in the results, between [1] and [2], for the GDE in the null vector field case due to an algebraic error in our original paper. As we expect, the expressions are consistent with the null energy condition (NEC) in f (R) gravity [3].…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…(32)], there is an additional contribution to E 2 in the operators, which is missing. The method used in [2] relies in the 1 + 3 decomposition, and for the FLRW, it is equivalent to the 3 + 1 where the four-velocity field for threading the spacetime is the four-velocity of the fundamental observers. The r.h.s.…”

Section: Geodesic Deviation Equation For the Flrw Universementioning

confidence: 99%

Erratum to: Geodesic deviation equation in f(R) gravity

2015

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In the context of metric f (R) gravity, the geodesic deviation equation (GDE) was first studied in Guarnizo et al. (Gen Relativ Gravit 43:2713-2728, giving a general expression and studying a particular case, the FLRW universe. In the paper (De la Cruz-Dombris et al. Physical Review D 89:064029-2014) a similar analysis was made. However, there is a discrepancy in the expressions for the null vector field case due to an algebraic error in our original paper. Here, we make explicit the contribution of the different operators in the GDE, and we correct our previous results.

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“…Hence it seems reasonable to affirm that extended gravity theories cannot be ruled out, definitively, using Solar System experiments [53][54][55][56]. Given the fact that f (R) theories of gravity with certain restriction on its parameters pass through both cosmological and local gravity tests, can be a strong candidate for explaining gravity at high energies [57][58][59][60][61][62][63][64][65][66][67].…”

Section: Introductionmentioning

confidence: 99%

Spherically symmetric brane in a bulk of f(R) and Gauss-Bonnet Gravity

Chakraborty,

SenGupta

2015

Preprint

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Effective gravitational field equations on a four dimensional brane embedded in a five dimensional bulk have been considered. Using the Einstein-Hilbert action along with the Gauss-Bonnet correction term, we have derived static spherically symmetric vacuum solution to the effective field equations, first order in the Gauss-Bonnet coupling parameter. The solution so obtained, has one part corresponding to general relativity with an additional correction term, proportional to the Gauss-Bonnet coupling parameter. The correction term modifies the spacetime structure, in particular, the location of the event horizon. Proceeding further, we have derived effective field equations for f (R) gravity with Gauss-Bonnet correction term and a static spherically symmetric solution has been obtained. In this case the Gauss-Bonnet term modifies both the event and cosmological horizon of the spacetime. There exist another way of obtaining the brane metric -expanding the bulk gravitational field equations in the ratio of bulk to brane curvature scale and assuming a separable bulk metric ansatz. It turns out that static, spherically symmetric solutions obtained from this perturbative method can be matched exactly, with the solutions derived earlier. This will hold for Einstein-Hilbert plus Gauss-Bonnet as well as for f(R) with the Gauss-Bonnet correction. Implications of these results are discussed.

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Tidal forces inf(R)theories of gravity

Cited by 16 publications

References 100 publications

Cosmic acceleration from matter–curvature coupling

Cosmic acceleration from matter–curvature coupling

Erratum to: Geodesic deviation equation in f(R) gravity

Spherically symmetric brane in a bulk of f(R) and Gauss-Bonnet Gravity

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