Erratum to: Scalar–vector–tensor gravity from preferred reference frame effects

Dehghani

2019

Eur. Phys. J. C

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As an alternative to dark matter models we use generalized Jordan-Brans-Dicke scalar-vector-tensor (JBD-SVT) gravity model to study the behavior of the rotational velocities of test particles moving around galaxies. To do so we consider an interaction potential U (φ, N µ ) between the Brans-Dicke scalar field φ and time like dynamical fourvector field N µ which plays as four velocity of a preferred reference frame. We show that at in weak field limits metric solution of the galaxy under consideration reaches to a modified Schwarzschild-de Sitter space in which mass of the vector field plays as an effective cosmological constant. In fact the present work proposes modification on the formulation of Newton's gravitational acceleration. This is used to explain circular velocity of galaxies without postulating dark matter. We also check our theoretical results with empirical baryonic Tully Fisher relation which states a linear relations between the rotational speed of galaxies and their mass. Mathematical calculation predict a good correspondence between our theoretical results and experimental observations for a set of 12 spiral galaxies.

Section: Introductionmentioning

confidence: 99%

Galaxy rotation curves and preferred reference frame effects

Dehghani

2019

Eur. Phys. J. C

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“…Organization of the paper is as follows. In section 2, we introduce the scalar-vector-tensor gravity model [10,11] under consideration. In section 3, we use the Bianchi I type of the background metric to obtain exact form of Hamiltonian density.…”

Section: Introductionmentioning

confidence: 99%

Canonical quantization of anisotropic Bianchi I cosmology from scalar vector tensor Brans Dicke gravity

2019

J. Phys.: Conf. Ser.

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We applied a generalized scalar-vector-tensor Brans Dicke gravity model to study canonical quantization of an anisotropic Bianchi I cosmological model. Regarding an anisotropic Harmonic Oscillator potential we show that the corresponding Wheeler de Witt wave functional of the system is described by Hermit polynomials. We obtained a quantization condition on the ADM mass of the cosmological system which raises versus the quantum numbers of the Hermit polynomials. Our calculations show that the inflationary expansion of the universe can be originate from the big bang with no naked singularity due to the uncertainty principle.

“…[21,22] for their experimental constraints). If dynamical vector fields to be have unit-time-like property then the scalar-vector-tensor gravities can be also support metric signature transition dynamics from Euclidean (+,+,+,+) to Lorentzian (-,+,+,+) signature (see [3] and reference therein). In short, the model presented in ref.…”

Section: Introductionmentioning

confidence: 99%

“…In short, the model presented in ref. [3] is generalized BD gravity [2] by transforming the background metric g µν to g µν + 2N µ N ν . Flat FRW quantum cosmology of the model and its metric signature transition property were studied in refs.…”

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

See 1 more Smart Citation

Dynamical system approach to scalar–vector–tensor cosmology

Yaraie

2017

Gen Relativ Gravit

Using scalar-vector-tensor Brans Dicke (VBD) gravity [3] in presence of self interaction BD potential V (φ) and perfect fluid matter field action we solve corresponding field equations via dynamical system approach for flat Friedmann Robertson Walker metric (FRW). We obtained 3 type critical points for ΛCDM vacuum de Sitter era where stability of our solutions are depended to choose particular values of BD parameter ω. One of these fixed points is supported by a constant potential which is stable for ω < 0 and behaves as saddle (quasi stable) for ω ≥ 0. Two other ones are supported by a linear potential V (φ) ∼ φ which one of them is stable for ω = 0.27647. For a fixed value of ω there is at least 2 out of 3 critical points reaching to a unique critical point. Namely for ω = −0.16856(−0.56038) the second (third) critical point become unique with the first critical point. In dust and radiation eras we obtained 1 critical point which never become unique fixed point. In the latter case coordinates of fixed points are also depended to ω. To determine stability of our solutions we calculate eigenvalues of Jacobi matrix of 4D phase space dynamical field equations for de Sitter, dust and radiation eras. We should be point also potentials which support dust and radiation eras must be similar to V (φ) ∼ φ − 1 2 and V (φ) ∼ φ −1 respectively. In short our study predicts that radiation and dust eras of our VBD-FRW cosmology transmit to stable de Sitter state via non-constant potential (effective variable cosmological parameter) by choosing ω = 0.27647.