Back to Search
Start Over
A study of perturbations in scalar-tensor theory using covariant approach.
- Source :
-
International Journal of Modern Physics D: Gravitation, Astrophysics & Cosmology . Feb2018, Vol. 27 Issue 3, p-1. 21p. - Publication Year :
- 2018
-
Abstract
- This work discusses scalar-tensor theories of gravity, with a focus on the Brans-Dicke sub-class, and one that also takes note of the latter's equivalence with gravitation theories. A covariant formalism is used in this case to discuss covariant perturbations on a background Friedmann-Laimaître-Robertson-Walker (FLRW) spacetime. Linear perturbation equations are developed based on gauge-invariant gradient variables. Both scalar and harmonic decompositions are applied to obtain second-order equations. These equations can then be used for further analysis of the behavior of the perturbation quantities in such a scalar-tensor theory of gravitation. Energy density perturbations are studied for two systems, namely for a scalar fluid-radiation system and for a scalar fluid-dust system, for models. For the matter-dominated era, it is shown that the dust energy density perturbations grow exponentially, a result which agrees with those already existing in the literatures. In the radiation-dominated era, it is found that the behavior of the radiation energy-density perturbations is oscillatory, with growing amplitudes for , and with decaying amplitudes for . This is a new result. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02182718
- Volume :
- 27
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- International Journal of Modern Physics D: Gravitation, Astrophysics & Cosmology
- Publication Type :
- Academic Journal
- Accession number :
- 127978463
- Full Text :
- https://doi.org/10.1142/S0218271818500335