scholarly journals Early universe with modified scalar-tensor theory of gravity

2018 ◽  
Vol 2018 (5) ◽  
Author(s):  
Ranajit Mandal ◽  
Chandramouli Sarkar ◽  
Abhik Kumar Sanyal
Keyword(s):  
Early Universe ◽  
Scalar Tensor Theory ◽  
Tensor Theory ◽  
Theory Of Gravity

scholarly journals Field Independent Cosmic Evolution

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Nayem Sk ◽  
Abhik Kumar Sanyal
Keyword(s):  
Higher Order ◽  
Noether Symmetry ◽  
Scalar Tensor Theory ◽  
Anisotropic Model ◽  
Tachyonic Field ◽  
Tensor Theory ◽  
Cosmic Evolution ◽  
Field Independent ◽  
Conserved Current ◽  
Theory Of Gravity

It has been shown earlier that Noether symmetry does not admit a form of corresponding to an action in which is coupled to scalar-tensor theory of gravity or even for pure theory of gravity taking anisotropic model into account. Here, we prove that theory of gravity does not admit Noether symmetry even if it is coupled to tachyonic field and considering a gauge in addition. To handle such a theory, a general conserved current has been constructed under a condition which decouples higher-order curvature part from the field part. This condition, in principle, solves for the scale-factor independently. Thus, cosmological evolution remains independent of the form of the chosen field, whether it is a scalar or a tachyon.

GALACTIC AND ASTROPHYSICAL SIZES FROM SCALAR-TENSOR THEORY OF GRAVITY

2004 ◽  
Vol 13 (02) ◽  
pp. 359-371 ◽  
Author(s):  
GIUSEPPE BASINI ◽  
MARCO RICCI ◽  
FULVIO BONGIORNO ◽  
SALVATORE CAPOZZIELLO
Keyword(s):  
Scalar Field ◽  
Spiral Galaxies ◽  
Weak Field ◽  
Newtonian Potential ◽  
Scalar Tensor Theory ◽  
Field Limit ◽  
Weak Field Limit ◽  
Tensor Theory ◽  
Flat Rotation Curves ◽  
Theory Of Gravity

We investigate the weak-field limit of scalar-tensor theory of gravity and show that results are directly depending on the coupling and self-interaction potential of the scalar field. In particular, corrections are derived for the Newtonian potential. We discuss astrophysical applications of the results, in particular the flat rotation curves of spiral galaxies.

scholarly journals Torsional oscillations of neutron stars in scalar-tensor theory of gravity

2014 ◽  
Vol 90 (12) ◽  
Author(s):  
Hector O. Silva ◽  
Hajime Sotani ◽  
Emanuele Berti ◽  
Michael Horbatsch
Keyword(s):  
Neutron Stars ◽  
Scalar Tensor Theory ◽  
Torsional Oscillations ◽  
Tensor Theory ◽  
Theory Of Gravity

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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