Dark Energy and Cosmological Horizon Thermal Effects

TL;DR

This paper explores how thermal effects from Hawking radiation influence dark energy models and the universe's evolution, including singularities and phase transitions, providing insights into cosmic acceleration and potential singularity remedies.

Contribution

It introduces the impact of Hawking radiation-induced thermal effects on dark energy models and their role in cosmic singularities and phase transitions.

Findings

Thermal effects can alter the nature of future singularities.

Transition between deceleration and acceleration is possible with quintessence.

Certain fluid components may prevent Big Rip singularities.

Abstract

We investigate various dark energy models by taking into account the thermal effects induced from Hawking radiation on the apparent horizon of the Universe, for example near a finite-time future singularity. If the dark energy density increases as the Universe expands, the Universe's evolution reaches a singularity of II type (or sudden future singularity). The second derivative of scale factor diverges but the first remains finite. Quasi-de Sitter evolution can change on sudden future singularity in the case of having an effective cosmological constant larger than the maximum possible value of the energy density of the Universe. Another interesting feature of cosmological solution is the possibility of a transition between deceleration and acceleration for quintessence dark energy with a simple equation of state. Finally, we investigate which fluid component can remedy Big Rip singularities and other crushing type singularities.