Thermodynamical study of FRW universe in Quasi-Topological Theory

TL;DR

This paper explores the thermodynamics of the apparent horizon in a Friedmann-Robertson-Walker universe within quasi-topological gravity, deriving entropy relations and examining the second law under various conditions.

Contribution

It derives the entropy relation for the apparent horizon in quasi-topological gravity using thermodynamic laws and analyzes the effects of cosmic interactions on entropy and thermodynamic laws.

Findings

Entropy expression matches other approaches when no energy exchange occurs.

Mutual interactions influence the apparent horizon entropy.

Second law of thermodynamics holds under certain conditions.

Abstract

By applying the unified first law of thermodynamics on the apparent horizon of FRW universe, we get the entropy relation for the apparent horizon in quasi-topological gravity theory. Throughout the paper, the results of considering the Hayward-Kodama and Cai-Kim temperatures are also addressed. Our study shows that whenever, there is no energy exchange between the various parts of cosmos, we can get an expression for the apparent horizon entropy in quasi-topological gravity, which is in agreement with other attempts followed different approaches. The effects of a mutual interaction between the various parts of cosmos on the apparent horizon entropy as well as the validity of second law of thermodynamics in quasi-topological gravity are also perused.