scholarly journals Inflation with Scalar-Tensor Theory of Gravity

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1267
Author(s):  
Dalia Saha ◽  
Susmita Sanyal ◽  
Abhik Kumar Sanyal
Keyword(s):  
Present Article ◽  
Power Law ◽  
Coupling Parameter ◽  
Scalar Tensor Theory ◽  
Tensor Theory ◽  
Theory Of Gravity ◽  
Inflationary Parameters

The latest released data from Planck in 2018 put up tighter constraints on inflationary parameters. In the present article, the in-built symmetry of the non-minimally coupled scalar-tensor theory of gravity is used to fix the coupling parameter, the functional Brans–Dicke parameter, and the potential of the theory. It is found that all the three different power-law potentials and one exponential pass these constraints comfortably, and also gracefully exit from inflation.

scholarly journals Scalar–tensor theories of gravity: validity of the cosmic no-hair conjecture

2011 ◽  
Vol 89 (9) ◽  
pp. 937-940
Author(s):  
Sudeshna Mukerji ◽  
Nairwita Mazumder ◽  
Ritabrata Biswas ◽  
Subenoy Chakraborty
Keyword(s):  
Coupling Parameter ◽  
Matter Field ◽  
Einstein Frame ◽  
Energy Conditions ◽  
Jordan Frame ◽  
Scalar Tensor Theory ◽  
Bianchi Models ◽  
Tensor Theory ◽  
Theories Of Gravity ◽  
Theory Of Gravity

This paper deals with the cosmic no-hair conjecture for anisotropic Bianchi models in the scalar–tensor theory of gravity. Herein, we have considered both the Jordan frame and the Einstein frame to describe the scalar–tensor theory of gravity and examine the conjecture. In the Jordan frame, one should restrict both the coupling function of the scalar field and the coupling parameter, in addition to the usual energy conditions for the matter field, to maintain the validity of the cosmic no-hair conjecture, while in the Einstein frame, the restrictions are purely on the energy conditions.

scholarly journals Superdense Stellar Configurations in the Bimetric Scalar-Tensor Theory of Gravity

2018 ◽  
pp. 327-337
Author(s):  
L. Sh. Grigorian ◽  
H. F. Khachatryan ◽  
A. A. Saharian
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Neutron Stars ◽  
White Dwarfs ◽  
Coupling Parameter ◽  
Spherically Symmetric ◽  
Scalar Tensor Theory ◽  
Metric Tensor ◽  
Tensor Theory ◽  
Theory Of Gravity

Models of static spherically-symmetric stellar configurations are discussed within the framework of the Bimetric scalar-tensor theory of gravity. The latter, in addition to the metric tensor and the scalar field, contains a background metric tensor as an absolute variable of the theory. The simplest variant of the theory with a constant coupling parameter and with a zero cosmological function is considered. The analysis includes both the white dwarfs and neutron stars. It is shown that, depending on the value of the theory parameter, the corresponding masses can be notably larger than those in general relativity.

Inflationary constraints in teleparallel gravity theory

2020 ◽  
pp. 2150027
Author(s):  
Shambel Sahlu ◽  
Joseph Ntahompagaze ◽  
Amare Abebe ◽  
David F. Mota
Keyword(s):  
Observational Data ◽  
Spectral Index ◽  
Power Law ◽  
Teleparallel Gravity ◽  
Gravity Models ◽  
Index Formula ◽  
Scalar Tensor Theory ◽  
Tensor Theory ◽  
Slow Roll ◽  
Inflationary Parameters

In this work, the cosmological inflationary parameters in the correspondence of teleparallel gravity for the scalar–tensor theory are investigated. After the review of [Formula: see text] and [Formula: see text] gravity cosmology, we use the slow-roll approximations to study the behavior of the inflationary parameters namely the spectral index [Formula: see text] and tensor-to-scalar ratio [Formula: see text], and a comparison with observational data for different paradigmatic [Formula: see text] gravity models such as exponential, Linder and power-law models is considered. We also consider the boundary term [Formula: see text] associated with these three models. The obtained behavior of the parameters under consideration shows that it is possible to constrain [Formula: see text] and [Formula: see text] models based on observational data.

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 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 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
Sign in / Sign up

Export Citation Format

Share Document