Cosmological Model for the Very Early Universe in B.D. Theory

TL;DR

This paper explores early universe cosmology within Brans-Dicke theory, showing that models behave similarly to those in General Relativity, especially regarding inflationary phases under specific equations of state.

Contribution

It extends previous work on early universe equations of state to Brans-Dicke cosmology, demonstrating similar inflationary behavior as in General Relativity.

Findings

Models in Brans-Dicke theory resemble those in General Relativity.

The universe enters an exponential inflationary phase under certain conditions.

The equation of state p=-(1/3)rho plays a key role in early universe dynamics.

Abstract

Following a paper by Berman and Marinho Jr (2001), where it was established an equation of state (p=-(1/3)rho), for the very early Universe, under which, Einstein's equations with lambda=0, render a scale-factor proportional to the time coordinate, and under which, Berman(2006, 2006a) showed that in the non-null lambda case, the Universe entered automatically into an exponential inflationary phase, we now study the corresponding effect in Brans-Dicke Cosmology. We find that the resulting models are similar to those in General Relativity Cosmology.