The conformal status of ο = -3/2 Brans-Dicke cosmology

Dąbrowski, Mariusz P.; Denkiewicz, Tomasz; Blaschke, D.

doi:10.1002/andp.200610230

Cited by 38 publications

(45 citation statements)

References 51 publications

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“…An ω 0 = 0 Brans-Dicke theory [sometimes called "massive dilaton gravity" (Wands, 1994)] was originally proposed by (O' Hanlon, 1972) in order to generate a Yukawa term in the Newtonian limit and has been occasionally considered in the literature (Anderson, 1971;Barber, 2003;Dabrowski et al, 2007;Davidson, 2005;Deser, 1970;Fujii, 1982;O'Hanlon and Tupper, 1972). The field equations corresponding to the action (54) are…”

Section: A Metric Formalismmentioning

confidence: 99%

Metric-affine f(R) theories of gravity

2007

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Modified gravity theories have received increased attention lately due to combined motivation coming from high-energy physics, cosmology and astrophysics. Among numerous alternatives to Einstein's theory of gravity, theories which include higher order curvature invariants, and specifically the particular class of f (R) theories, have a long history. In the last five years there has been a new stimulus for their study, leading to a number of interesting results. We review here f (R) theories of gravity in an attempt to comprehensively present their most important aspects and cover the largest possible portion of the relevant literature. All known formalisms are presentedmetric, Palatini and metric-affine -and the following topics are discussed: motivation; actions, field equations and theoretical aspects; equivalence with other theories; cosmological aspects and constraints; viability criteria; astrophysical applications.

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Section: A Metric Formalismmentioning

confidence: 99%

Metric-affine f(R) theories of gravity

2007

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“…The stringent observational bound resulting from the 2003 experiment with the Cassini spacecraft require that ∣ ω ∣ ≳ 40 000 [57, 418]. On the other hand, ω = −3/2 may be favored by cosmological observations and also offer a resolution of the Pioneer anomaly [85]. A possible resolution can be obtained by incorporating a Gauss-Bonnet term in the form of into the Brans-Dicke version of the Lagrangian Equation (6.12) with the choice of Equation (6.13), which may allow the Eddington parameter γ to be arbitrarily close to 1, while choosing an arbitrary value for ω [10].…”

Section: Efforts To Explain and Study The Anomalymentioning

confidence: 99%

The Pioneer Anomaly

Turyshev

Toth²

2010

Living Rev. Relativ.

136

148

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Radio-metric Doppler tracking data received from the Pioneer 10 and 11 spacecraft from heliocentric distances of 20–70 AU has consistently indicated the presence of a small, anomalous, blue-shifted frequency drift uniformly changing with a rate of ∼ 6 × 10−9 Hz/s. Ultimately, the drift was interpreted as a constant sunward deceleration of each particular spacecraft at the level of aP = (8.74 ± 1.33) × 10−10 m/s2. This apparent violation of the Newton’s gravitational inverse-square law has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained. In this review, we summarize the current knowledge of the physical properties of the anomaly and the conditions that led to its detection and characterization. We review various mechanisms proposed to explain the anomaly and discuss the current state of efforts to determine its nature. A comprehensive new investigation of the anomalous behavior of the two Pioneers has begun recently. The new efforts rely on the much-extended set of radio-metric Doppler data for both spacecraft in conjunction with the newly available complete record of their telemetry files and a large archive of original project documentation. As the new study is yet to report its findings, this review provides the necessary background for the new results to appear in the near future. In particular, we provide a significant amount of information on the design, operations and behavior of the two Pioneers during their entire missions, including descriptions of various data formats and techniques used for their navigation and radio-science data analysis. As most of this information was recovered relatively recently, it was not used in the previous studies of the Pioneer anomaly, but it is critical for the new investigation.

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“…Conformal transformations of the metric tensor [1] are interesting characteristics of the scalar-tensor theories of gravity [2][3][4][5], including its conformally invariant version [6][7][8][9]. The point is that these theories can be represented in the two conformally related frames: the Jordan frame in which the scalar field is non-minimally coupled to the metric tensor, and in the Einstein frame in which it is minimally coupled to the metric tensor.…”

Section: Introductionmentioning

confidence: 99%

Conformal transformations and conformal invariance in gravitation

Dąbrowski¹,

Garecki²,

Blaschke³

2009

Ann. Phys.

Self Cite

105

115

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Conformal transformations are frequently used tools in order to study relations between various theories of gravity and the Einstein relativity. In this paper we discuss the rules of these transformations for geometric quantities as well as for the matter energy-momentum tensor. We show the subtlety of the matter energy-momentum conservation law which refers to the fact that the conformal transformation "creates" an extra matter term composed of the conformal factor which enters the conservation law. In an extreme case of the flat original spacetime the matter is "created" due to work done by the conformal transformation to bend the spacetime which was originally flat. We discuss how to construct the conformally invariant gravity theories and also find the conformal transformation rules for the curvature invariants R 2 , R ab R ab , R abcd R abcd and the Gauss-Bonnet invariant in a spacetime of an arbitrary dimension. Finally, we present the conformal transformation rules in the fashion of the duality transformations of the superstring theory.In such a case the transitions between conformal frames reduce to a simple change of the sign of a redefined conformal factor.

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The conformal status of ο = -3/2 Brans-Dicke cosmology

Cited by 38 publications

References 51 publications

Metric-affine f(R) theories of gravity

Metric-affine f(R) theories of gravity

The Pioneer Anomaly

Conformal transformations and conformal invariance in gravitation

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