Thermodynamical properties of nonsingular universe

TL;DR

This paper investigates the thermodynamical properties of a nonsingular universe with zero-point length corrections, deriving modified cosmological equations, confirming the absence of initial singularity, and analyzing the universe's evolution and entropy behavior.

Contribution

It introduces zero-point length corrections into the thermodynamics of the apparent horizon, leading to modified Friedmann equations and a nonsingular cosmological model.

Findings

The initial singularity is removed in the model.

The universe's age is predicted to be larger than in standard cosmology.

The generalized second law of thermodynamics is satisfied.

Abstract

We disclose the thermodynamical properties of the apparent horizon in a nonsingular universe. We take into account the zero-point length correction to the gravitational potential and derive the modified entropy expression that includes zero-point length correction terms. We apply the first law of thermodynamics on the apparent horizon as well as the emergent gravity scenario to derive the modified Friedmann equations. Further, we examine the time evolution of the total entropy, including the entropy of the apparent horizon and the matter field entropy inside the horizon and find out that the generalized second law of thermodynamics is satisfied. We also investigate the cosmological implications of the modified cosmology through zero-point length. We observe that the zero-point length correction does not change the general profile of the universe evolution, however, it shifts the time of the phase transition in a universe filled with matter and cosmological constant. We explore the age of the universe for our model and observe that the predicted age of the universe becomes larger compared to the standard cosmology. By calculating the explicit form of Ricci and Kretchmann invariants, we confirm that in our model, the initial singularity of the universe is removed. This is an expected result, because the main motivation for considering zero-point length correction in the gravitational potential is to remove singularity at the origin.