Dark Energy With Polytropic Equation-of-State

Abstract

Equation of state parameter plays a significant role for guessing the real nature of dark energy. In the present paper polytropic equation of state p = ωρ n is chosen for some of the kinematical Λ-models viz., Λ ∼ (ȧ/a) 2 , Λ ∼ä/a and Λ ∼ ρ. Although in dust cases (ω = 0) closed form solutions show no dependency on the polytropic index n, but in non-dust situations some new possibilities are opened up including phantom energy with supernegative (ω < −1) equation of state parameter.

Tachyon-polytropic inflation on the brane

“…The polytropic constant K can take the positive value for radiation and stiff fluid, the zero value for dust and the negative value for inflationary scenario [21]. From equation of state (3) we can find squared speed of polytropic fluid as…”

“…On the other hand, the polytropic gas has been proposed as an alternative model for describing the acceleration of the universe [21]. The polytropic equation of state has been used in various astrophysical situations; for example, it can explain the equation of state of degenerate white dwarfs, neutron stars, the equation of state of main sequence stars [22], and in the case of Lane-Emden models [23,24].…”

A single model of traversable wormholes supported by generalized phantom energy or Chaplygin gas

“…Kuhfittig [12] assumes that K is both space and time dependent, i.e., K = K (r, t). Evolving equations of state are also discussed in [13][14][15].…”

Warm-Polytropic Inflationary Universe Model

“…On the other hand, the polytropic gas has been proposed as an alternative model for describing the accelerating of the universe [11]. Polytropic equation of state has been used in various astrophysical situations, for example it can explain the equation of state of degenerate white dwarfs, neutron stars and also the equation of state of main sequence stars [12], and in the case of Lane-Emden models [13,14].…”