Bianchi I in scalar and scalar-tensor cosmologies

Belinchón, José Antonio

doi:10.2478/s11534-012-0087-y

Cited by 7 publications

(3 citation statements)

References 58 publications

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“…A number of anisotropic cosmological solutions of the Brans-Dicke field equations are also known. Bianchi type-I solutions have been found in [1075,133], type-II in [822,580,825], type-III solutions in [826], type-V solutions in [821,823,827,828,581], type-V I 0 and V I h solutions in [829,830,131], type-V II h solutions in [824,579], type-V III solutions in [825,820], type-IX solutions in [825,820], and Kantowski-Sachs solutions in [826]. Inhomogeneous cosmological solutions have also been found [313], and braneworld cosmologies have been considered in [75,1054].…”

Section: Brans-dicke Theorymentioning

confidence: 99%

Modified Gravity and Cosmology

Clifton,

Ferreira,

Padilla

et al. 2011

Preprint

501

847

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In this review we present a thoroughly comprehensive survey of recent work on modified theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, Scalar-Tensor, Einstein-Aether, and Bimetric theories, as well as TeVeS, f (R), general higher-order theories, Hořava-Lifschitz gravity, Galileons, Ghost Condensates, and models of extra dimensions including Kaluza-Klein, Randall-Sundrum, DGP, and higher co-dimension braneworlds. We also review attempts to construct a Parameterised Post-Friedmannian formalism, that can be used to constrain deviations from General Relativity in cosmology, and that is suitable for comparison with data on the largest scales. These subjects have been intensively studied over the past decade, largely motivated by rapid progress in the field of observational cosmology that now allows, for the first time, precision tests of fundamental physics on the scale of the observable Universe. The purpose of this review is to provide a reference tool for researchers and students in cosmology and gravitational physics, as well as a self-contained, comprehensive and up-to-date introduction to the subject as a whole.

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Section: Brans-dicke Theorymentioning

confidence: 99%

Modified Gravity and Cosmology

Clifton,

Ferreira,

Padilla

et al. 2011

Preprint

501

847

View full text Add to dashboard Cite

show abstract

“…Furthermore working under the hypothesis of selfsimilarity allows us to find exact power-law solutions in such a way that we may compare the obtained solution for each studied model. By applying the theoretical results obtained in [20] we have studied how may vary and Λ in the described theoretical models using different geometries as Bianchi I [25], Bianchi II [26], Bianchi V, VII ℎ and IX [27] and Kantowsky-Sach [20]. In this paper, enlarging the program, we would like to study the case of family of Bianchi VI geometry, that is, Bianchi III, VI 0 , and VI ℎ .…”

Section: Journal Of Gravitymentioning

confidence: 99%

Scalar-Tensor Bianchi VI Models

Belinchón

2013

Journal of Gravity

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We study how may vary the gravitational and the cosmological “constants,” ( and ) in several scalar-tensor theories with Bianchi III, , and symmetries. By working under the hypothesis of self-similarity we find exact solutions for two different theoretical models, which are the Jordan-Brans-Dicke (JBD) with and the usual JBD model with potential (that mimics the behaviour of . We compare both theoretical models, and some physical and geometrical properties of the solutions are also discussed putting special emphasis on the study of the isotropization of the solutions.

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“…There has been considerable interest in cosmologies with variable parameters ever since. See [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] for recent studies and the references cited in [13] for citations to earlier research on the topic. These models considered either or both and Λ to be time-dependent.…”

Section: Introductionmentioning

confidence: 99%

A Time-DependentΛandGCosmological Model Consistent with Cosmological Constraints

Kantha

2016

Advances in Astronomy

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The prevailing constantΛ-Gcosmological model agrees with observational evidence including the observed red shift, Big Bang Nucleosynthesis (BBN), and the current rate of acceleration. It assumes that matter contributes 27% to the current density of the universe, with the rest (73%) coming from dark energy represented by the Einstein cosmological parameterΛin the governing Friedmann-Robertson-Walker equations, derived from Einstein’s equations of general relativity. However, the principal problem is the extremely small value of the cosmological parameter (~10−52 m2). Moreover, the dark energy density represented byΛis presumed to have remained unchanged as the universe expanded by 26 orders of magnitude. Attempts to overcome this deficiency often invoke a variableΛ-Gmodel. Cosmic constraints from action principles require that either bothGandΛremain time-invariant or both vary in time. Here, we propose a variableΛ-Gcosmological model consistent with the latest red shift data, the current acceleration rate, and BBN, provided the split between matter and dark energy is 18% and 82%.Λdecreases (Λ~τ-2, whereτis the normalized cosmic time) andGincreases (G~τn) with cosmic time. The model results depend only on the chosen value ofΛat present and in the far future and not directly onG.

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Bianchi I in scalar and scalar-tensor cosmologies

Cited by 7 publications

References 58 publications

Modified Gravity and Cosmology

Modified Gravity and Cosmology

Scalar-Tensor Bianchi VI Models

A Time-DependentΛandGCosmological Model Consistent with Cosmological Constraints

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