Brans-Dicke models with time-dependent cosmological term

Berman, Marcelo Samuel; Som, M. M.

doi:10.1007/bf00674120

Cited by 82 publications

(61 citation statements)

References 6 publications

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“…It is believed that β 2 has similar behaviour as the cosmological constant which decreases during expansion of universe. Several authors [53]− [65] have considered the relation β ∼ 1 t for study of cosmological models in different context.…”

Section: Physical Consequences Of the Modelsmentioning

confidence: 99%

Plane symmetric bulk viscous domain wall in Lyra geometry

Pradhan

Kumar

Yadav³

2007

Braz. J. Phys.

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In this paper general solutions are found for domain walls in Lyra geometry in the plane symmetric spacetime metric given by Taub. Expressions for the energy density and pressure of domain walls are derived in both cases of uniform and time varying displacement field β. Some physical consequences of the models are also given. Finally, the geodesic equations and acceleration of the test particle are discussed.

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Section: Physical Consequences Of the Modelsmentioning

confidence: 99%

Plane symmetric bulk viscous domain wall in Lyra geometry

Pradhan

Kumar

Yadav³

2007

Braz. J. Phys.

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“…theory with power-law scale-factors and time-dependent cosmological terms. At the same time, Berman (1991a) studied the same problem in General Relativity, and, then, a variable gravitational constant in an ad-hoc general relativistic format, was dealt with by Berman (1991b Berman and Som (1990) studied the same problem in the context of a B.D. theory endowed with a variable cosmological "constant".…”

Section: Introductionmentioning

confidence: 96%

Static scalar-tensor universes and gravitational waves’ amplification

Berman

2009

Astrophys Space Sci

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“…The calculations of quantum field theory predict the value of vacuum to be of the order of 10 130 s −2 , whereas the cosmological constant value is of the order of 10 −20 s −2 ; hence, a new thought is required to explain or resolve this puzzle. The idea of considering the cosmological models as varying vacuum energy density Λ has extensively been adapted by several authors [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

A Generalized Solution of Bianchi Type-V Models with Time-Dependent G and Λ

2018

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Abstract:We study the homogeneous but anisotropic Bianchi type-V cosmological model with time-dependent gravitational and cosmological "constants". Exact solutions of the Einstein field equations (EFEs) are presented in terms of adjustable parameters of quantum field theory in a spatially curved and expanding background. It has been found that the general solution of the average scale factor a as a function of time involved the hypergeometric function. Two cosmological models are obtained from the general solution of the hypergeometric function and the Emden-Fowler equation.The analysis of the models shows that, for a particular choice of parameters in our first model, the cosmological "constant" decreases whereas the Newtonian gravitational "constant" increases with time, and for another choice of parameters, the opposite behaviour is observed. The models become isotropic at late times for all parameter choices of the first model. In the second model of the general solution, both the cosmological and gravitational "constants" decrease while the model becomes more anisotropic over time. The exact dynamical and kinematical quantities have been calculated analytically for each model.

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Brans-Dicke models with time-dependent cosmological term

Cited by 82 publications

References 6 publications

Plane symmetric bulk viscous domain wall in Lyra geometry

Plane symmetric bulk viscous domain wall in Lyra geometry

Static scalar-tensor universes and gravitational waves’ amplification

A Generalized Solution of Bianchi Type-V Models with Time-Dependent G and Λ

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