Cosmological models with constant deceleration parameter in Brans-Dicke theory

TLDR: In this article, a detailed study of cosmological models with constant deceleration parameterq is undertaken in the framework of Brans-Dicke theory, and the role played by the BD scalar field and creation of matter particles in the expansion of the universe is investigated.

Abstract: A detailed study of cosmological models with constant deceleration parameterq is undertaken in the framework of Brans-Dicke theory. These models are divided into two categories: (i) singular models with expansion driven by big-bang impulse, (ii) non-singlar models with expansion driven by creation of matter particles. Prigogine's hypothesis of creation of matter out of gravitational energy is analysed and extended to BD cosmology. To accommodate the creation of new particles, the universe is regarded as an open thermodynamical system and the energy conservation equation is modified with the incorporation of a creation pressure termp c in the energy-momentum tensor $$\tilde T_{ab} $$ . The exact solutions of the field equations of BD theory with $$\tilde T_{ab} $$ are obtained using the power law relationΦ=KR α, which leads to models with constantq. The behaviour of the solutions is investigated for different range of values ofa. The role played by the BD scalar fieldΦ and creation of matter particles in the expansion of the universe is investigated. It is found that one particular model with constantq has exponential expansion.