Thermodynamical and observational aspects of cosmological model with linear equation of state

Abstract

In this paper, a cosmological model with linear equation of state in the framework of General relativity is studied. We explore the thermodynamical aspects of the cosmological model with equilibrium description. In particular, we discuss the validity of generalized second law of thermodynamics for resulting cosmologies. General conditions for this model to satisfy the slow roll conditions for inflation are discussed.

Qualitative study of anisotropic Rastall cosmologies

“…The de Sitter, accelerating power-law expansion can be achieved for q = −1 and −1 < q < 0 respectively. For q < −1, super-exponential expansion scenario exists [45][46][47][48][49]. It have been confirmed by observational results that the universe is currently expanding with acceleration and it has been decelerating in the past [50].…”

Qualitative aspects of Rastall gravity with barotropic fluid

“…If α and ρ are small enough as compared to ρ 0 in any scenario, then we may get negative pressure in the model. In this paper, we take perfect fluid with following barotropic equation of state which have also been investigated in different cosmological set-ups as [60][61][62][63]…”

“…'Barotropic fluid' means some matter or field with equation of state p = f (ρ). Barotropic fluids have long been studied in the context of dark energy [28,[60][61][62][63][64][65][66].…”

“…From thermodynamics point of view in cosmological scenario, the enveloping surface should be apparent horizon and not the event horizon [74]. Apparent horizon as universe's boundary have been used in literature for examining the validity of GSLT in different cosmological set-ups [19,23,25,52,55,57,61,73,74]. In flat-FRW universe, radius of apparent horizon is related with Hubble parameter as R a = 1 H .…”

Variable Chaplygin gas cosmologies in f(R, T) gravity with particle creation

“…The idea of particle production in different theories of gravity have been extensively studied in literature . The barotropic fluids and extensions of barotropic equation of state p = γρ which are built up with different equation of state [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] presents relevant examples of perfect fluids. The forms of barotropic fluids dubbed as Chaplygin gas [50,51] and generalizations of Chaplygin gas [52][53][54] have also been used in literature to interpolate between an early time decelerated phase and late time accelerated expansion phase.…”