Thermodynamics in the Universe Described by the Emergence of Space and the Energy Balance Relation.

Fei-Quan Tu,Qi-Hong Huang,Yi-Xin Chen

doi:10.3390/e21020167

Abstract

It has previously been shown that it is more common to describe the evolution of the universe based on the emergence of space and the energy balance relation. Here we investigate the thermodynamic properties of the universe described by such a model. We show that the first law of thermodynamics and the generalized second law of thermodynamics (GSLT) are both satisfied and the weak energy condition are also fulfilled for two typical examples. Finally, we examine the physical consistency for the present model. The results show that there exists a good thermodynamic description for such a universe.

Highlights

Numerous astro-observations show that our universe is in accelerating expansion at present [1,2].There are usually two ways to explain the phenomenon if we consider the evolution of the universe from the point of view of the dynamics of gravity
In Ref. [36], we considered the current accelerated expansion of the universe based on the emergence of space and the energy balance relation ρVH = TS, where ρ is the energy density of the cosmic matter, S = A H /(4L2p ) = πH −2 /L2p is the entropy associated with the area of the Hubble
We study the first law of thermodynamics and the generalized second law of thermodynamics (GSLT) in the universe described by the emergence of space and the energy balance relation

Summary

Introduction

Numerous astro-observations show that our universe is in accelerating expansion at present [1,2]. In this way, we obtain the dynamical evolution equations of the universe based on the emergence of space and the energy balance relation. We obtain the dynamical evolution equations of the universe based on the emergence of space and the energy balance relation It was shown [36] that it is more common to describe the evolution of the universe in such a thermodynamic way because the solutions of the dynamical evolution equations in such a model include the solutions obtained from the standard general relativity theory

First Law of Thermodynamics for the Present Model

Validity of the GSLT and Thermodynamic Equilibrium

Conclusions