Time Dependence of Cosmological Parameters in the Framework of Brans-Dicke Theory

Authors

  • Sudipto Roy  Department of Physics, St. Xavier's College, Kolkata, West Bengal, India
  • Avik Ghosh  Post Graduate Student of Physics (2017-2019), St. Xavier's College, Kolkata, India
  • Adrika Dasgupta  Post Graduate Student of Physics (2017-2019), St. Xavier's College, Kolkata, India

DOI:

https://doi.org//10.32628/IJSRST196536

Keywords:

Cosmology, Dark Energy, Brans-Dicke Theory, Gravitation, Cosmic Acceleration.

Abstract

In the framework of Brans-Dicke (BD) theory of gravitation, the time dependence of some cosmological parameters have been determined in the present study, for an universe having a FRW space-time with zero spatial curvature. The time variations of the energy density, BD parameter, equation of state (EoS) parameter have been determined, from the field equations of the BD theory, in the initial part of this model. For this purpose, we have used ansatzes relating the scalar field with the scale factor and also linking the BD parameter with the scalar field. For these calculations, an empirical expression for the scale factor has been used. This scale factor has been so chosen that it leads to a signature flip of the deceleration parameter from positive to negative in the course of its evolution with time, indicating a change of phase from decelerated expansion to accelerated expansion. Time dependence of the density parameters for matter and dark energy has also been studied here. Using their expressions we have determined the time dependence of the densities of matter and dark energy. The time variations of all these parameters have been shown graphically. Apart from them, we have also shown the variations of the deceleration parameter and the BD parameter as functions of the scalar field graphically.

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International Journal of Scientific Research in Science and Technology

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Published

2019-10-30

Issue

Volume 6, Issue 5, September-October-2019

Section

Research Articles

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How to Cite

[1]
Sudipto Roy, Avik Ghosh, Adrika Dasgupta, " Time Dependence of Cosmological Parameters in the Framework of Brans-Dicke Theory, International Journal of Scientific Research in Science and Technology(IJSRST), Online ISSN : 2395-602X, Print ISSN : 2395-6011, Volume 6, Issue 5, pp.242-254, September-October-2019. Available at doi : https://doi.org/10.32628/IJSRST196536