Solutions of a Cosmological Equation in the Scale Invariant Scalar-Tensor Theory of Gravitation

1983 ◽  
Vol 70 (2) ◽  
pp. 412-423 ◽  
Author(s):  
Y. Fujii ◽  
J. M. Niedra
Keyword(s):  
Scalar Tensor Theory ◽  
Scale Invariant ◽  
Tensor Theory ◽  
Cosmological Equation ◽  
Invariant Scalar ◽  
Theory Of Gravitation

scholarly journals Gravitoelectromagnetic inflation and seeds of cosmic magnetic fields from geometrical Weyl-invariant scalar–tensor theory of gravity

2019 ◽  
Vol 97 (5) ◽  
pp. 517-523 ◽  
Author(s):  
M. Montes ◽  
José Edgar Madriz Aguilar ◽  
V. Granados
Keyword(s):  
Magnetic Fields ◽  
Power Spectrum ◽  
Electromagnetic Potential ◽  
Scalar Tensor Theory ◽  
Scale Invariant ◽  
Inflaton Field ◽  
Tensor Theory ◽  
Invariant Scalar ◽  
Theory Of Gravity ◽  
Good Agreement

We investigate cosmological inflationary scenarios from a gravitoelectromagnetic theory. Our work is formulated in light of a recently introduced geometrical Weyl-invariant scalar–tensor theory of gravity, where the nature of both the electromagnetic potential and the inflaton field is attributed to the space–time geometry. We obtain a Harrison–Zeldovich power spectrum for quantum fluctuations of the inflaton field. In our model the electromagnetic fields also have a nearly scale-invariant power spectrum for a power-law inflation. We found that the seed magnetic fields have a nearly scale-invariant power spectrum and generate at the present time cosmic magnetic fields of the order ≲10−9 G, in good agreement with CMB observations.

scholarly journals Plane Symmetric Solutions of a Scalar-Tensor Theory of Gravitation

1977 ◽  
Vol 30 (1) ◽  
pp. 109 ◽  
Author(s):  
DRK Reddy
Keyword(s):  
General Relativity ◽  
Empty Space ◽  
Scalar Fields ◽  
Scalar Tensor Theory ◽  
Field Equations ◽  
Plane Symmetric ◽  
Zero Mass ◽  
Tensor Theory ◽  
Special Cases ◽  
Theory Of Gravitation

Plane symmetric solutions of a scalar-tensor theory proposed by Dunn have been obtained. These solutions are observed to be similar to the plane symmetric solutions of the field equations corresponding to zero mass scalar fields obtained by Patel. It is found that the empty space-times of general relativity discussed by Taub and by Bera are obtained as special cases.

scholarly journals Non-Riemannian description of Robinson–Trautman spacetimes in Brans–Dicke theory of gravity

2019 ◽  
Vol 28 (04) ◽  
pp. 1950070
Author(s):  
Muzaffer Adak ◽  
Tekin Dereli ◽  
Yorgo Şenikoğlu
Keyword(s):  
Scalar Field ◽  
Differential Forms ◽  
Scalar Tensor Theory ◽  
Field Equations ◽  
Exterior Differential ◽  
Tensor Theory ◽  
Theory Of Gravitation ◽  
Theory Of Gravity ◽  
Future Reference

The variational field equations of Brans–Dicke scalar-tensor theory of gravitation are given in a non-Riemannian setting in the language of exterior differential forms over four-dimensional spacetimes. A conformally rescaled Robinson–Trautman metric together with the Brans–Dicke scalar field are used to characterize algebraically special Robinson–Trautman spacetimes. All the relevant tensors are worked out in a complex null basis and given explicitly in an appendix for future reference. Some special families of solutions are also given and discussed.

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