Singular behavior of the dark universe under the effect of thermal radiation in curved spacetime

TL;DR

This paper explores how thermal radiation, viscosity, and curvature influence the formation and nature of singularities in the late-time accelerated universe, suggesting conditions under which a singularity-free universe can exist.

Contribution

It introduces a model analyzing the combined effects of Hawking radiation, viscosity, and curvature on cosmic singularities, revealing potential for singularity avoidance.

Findings

Hawking radiation can alter the timing and type of cosmological singularities.

Inclusion of viscosity and curvature can lead to a singularity-free universe.

Thermal effects and viscosity influence the universe's late-time behavior.

Abstract

We consider the late-time accelerated universe in the Friedmann-Robertson-Walker (FRW) spacetime with a nonzero curvature, and investigate cosmological models when the cosmic fluid is taken to be inhomogeneous and viscous (bulk viscous), coupled to dark matter. We consider the influence from thermal effects caused by Hawking radiation on the formation of singularities of various classified types, within a finite time. It is shown that under the influence of Hawking radiation the time of formulation of a singularity, and the nature of the singularity itself, can change. It is also shown that by jointly taking into account radiation, viscosity, and space curvature, one can obtain a singularity-free universe. The symmetry properties of this kind of theory lie in the assumption about spatial isotropy. The spatial isotropy is also reflected in our use of a bulk, instead of a shear, viscosity.