Generalising certain cosmological solutions sourced by a stiff perfect fluid

Abstract

In this article, we show that a number of well-known time-dependent, spherically symmetric solutions of the Einstein’s field equations sourced by a stiff, perfect fluid with a cosmological constant can be generalised into a solution with arbitrary metric functions. This metric can be applied to construct stiff, perfect fluid metrics with (or without) a cosmological constant. We also explore the possibility that this metric may allow us to generate a singularity-free, spherically symmetric cosmological model.