Will There Be Future Deceleration? A Study of Particle Creation Mechanism in Nonequilibrium Thermodynamics

Supriya Pan,Subenoy Chakraborty

doi:10.1155/2015/654025

Abstract

The paper deals with nonequilibrium thermodynamics based on adiabatic particle creation mechanism with the motivation of considering it as an alternative choice to explain the recent observed accelerating phase of the universe. Using Friedmann’s equations, it is shown that the deceleration parameter (q) can be obtained from the knowledge of the particle production rate (Γ). Motivated by thermodynamical point of view, cosmological solutions are evaluated for the particle creation rates in three cosmic phases, namely, inflation, matter dominated era, and present late time acceleration. The deceleration parameter (q) is expressed as a function of the redshift parameter (z), and its variation is presented graphically. Also, statefinder analysis has been presented graphically in three different phases of the universe. Finally, two noninteracting fluids with different particle creation rates are considered as cosmic substratum, and deceleration parameter (q) is evaluated. Whether more than one transition ofqis possible or not is examined by graphical representations.

Highlights

There was a dramatic change in our knowledge of the evolution history of the universe based on the standard cosmology at the end of the last century due to some observational predictions from type Ia Supernova [1, 2] and others [3, 4]
Riess et al [1] and Perlmutter et al [2] observed that distant Supernovae at redshift z ∼ 0.5 and Δm ∼ 0.25 mag are found to be about 25% fainter than the prediction from standard cosmology, and, they concluded that the universe at present is undergoing an accelerated expansion rather than deceleration
This present accelerating phase was supported by the cosmic microwave background (CMB) [3] and the baryon acoustic oscillations (BAO) [4]

Summary

Introduction

There was a dramatic change in our knowledge of the evolution history of the universe based on the standard cosmology at the end of the last century due to some observational predictions from type Ia Supernova [1, 2] and others [3, 4]. Introducing the uncertainty principle at the Planck’s epoch, it is found that the hierarchy of the universe’s energy scales is supported by the observational data This Hamiltonian dynamics of the model describe the effect of an intensive vacuum creation of gravitons and the minimal coupling scalar (Higgs) bosons in the early universe. The motivation of the present work in the framework of the particle creation mechanism comes from some recent related works It has been shown in [39, 40] that the entire cosmic evolution from inflationary stage can be described by particle creation mechanism with some specific choices of the particle creation rates.

Nonequilibrium Thermodynamics

Late Time Evolution

Field Theoretic Analysis and Particle Creation

Two Noninteracting Fluids as Cosmic Substratum and Particle Creations

Discussions and Future Prospects