A Study of Transition of the Expansion of the Universe from a Phase of Deceleration to Acceleration through a Conversion of Matter into Dark Energy in the Framework of Brans-Dicke Theory
Abstract: The present study is based on a generalized form of Brans-Dicke (BD) theory where, the dimensionless BD parameter is regarded as a function of the scalar field, which is reciprocal of the gravitational constant. The field equations have been solved by incorporating an empirical function f (t) in the expression representing the conservation of matter. This function f (t) has been chosen to account for a conversion of matter (both dark and baryonic) into some other form, possibly dark energy, which is known to be responsible for the accelerated expansion of universe. The requirement of a signature flip of the deceleration parameter (q), which is evident from other studies, sets the boundary conditions to be satisfied by the function f (t), leading to the formulation of its time dependence. A simple empirical relation was initially assumed to represent the time dependence of f (t), and the constants in this expression have been determined from these boundary conditions. The BD parameter has been found to have a negative value throughout the range of study. The dependence of BD parameter upon the scalar field has been depicted graphically. A smooth transition of the universe, from a decelerated to an accelerated phase of expansion, is found to occur due to a conversion of matter into dark energy. The gravitational constant is found to be increasing with time.
Keywords: Conversion of matter into dark energy, Signature flip of deceleration parameter, Time varying Gravitational constant, Generalized Brans-Dicke theory of Gravitation, Cosmology
How to Cite?: Sudipto Roy, "A Study of Transition of the Expansion of the Universe from a Phase of Deceleration to Acceleration through a Conversion of Matter into Dark Energy in the Framework of Brans-Dicke Theory", Volume 4 Issue 11, November 2015, International Journal of Science and Research (IJSR), Pages: 885-890, https://www.ijsr.net/getabstract.php?paperid=NOV151308, DOI: https://dx.doi.org/10.21275/NOV151308