A simple shear-free non-singular spherical model with heat flux

TL;DR

This paper presents the first known shear-free, spherically symmetric non-singular cosmological model with heat flux, derived from an exact Einstein equation solution, avoiding initial singularities like the big bang.

Contribution

It introduces the first shear-free, non-singular spherical model with heat flux, expanding the class of singularity-free solutions in cosmology.

Findings

Model satisfies weak and strong energy conditions.

Heat flux and pressure gradient prevent singularity.

Model is shear-free and spherically symmetric.

Abstract

We obtain an exact simple solution of the Einstein equation describing a spherically symmetric cosmological model without the big-bang or any other kind of singularity. The matter content of the model is shear free isotropic fluid with radial heat flux and it satisfies the weak and strong energy conditions. It is pressure gradient combined with heat flux that prevents occurrence of singularity. So far all known non-singular models have non-zero shear. This is the first shear free non-singular model, which is also spherically symmetric.