Thermodynamic behavior and stability of Polytropic gas

In this paper, at first, we focus on a FRW universe in which the dark energy candidate satisfies the Polytropic equation of state and study thermodynamics of dark energy. Bearing the thermal fluctuation theorem in mind, we establish a relation between the thermal fluctuation of system and mutual interaction between the dark energy and dark matter. Generalization to a viscous Polytropic gas is also investigated. We point to a condition for decaying dark energy candidate into the dark matter needed for alleviating coincidence problem. The effects of dark energy candidates and their interactions with other parts of cosmos on the horizon entropy as well as the second law of thermodynamics are also addressed. Our study signals us to a correction term besides the Bekenstein entropy which carries the information of the dark energy candidate, its interaction with other parts of cosmos and its viscosity.

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“…where we have used Eqs. (35) and (39) to obtain this equation. It is useful to note here that although this equation is similar to Eq.…”

Section: Interacting Viscous Polytropic Modelmentioning

confidence: 99%

Thermodynamic descriptions of polytropic gas and its viscous type as dark energy candidates

Moradpour

Sabet

2016

Can. J. Phys.

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“…Originally, Thakurta (1981) have used this technique and obtained a dynamical version of the Schwarzschild BH [17]. Since the Thakurta spacetime is a conformal transformation of the Schwarzschild metric, it is now accepted that its redshift radii points to the co-moving radii of the event horizon of BH [16,18,19]. By considering asymptotic behavior of the gravitational lagrangian (Ricci scalar), one can classify the Thakurta BH and its extension to the charged BH into the same class of solutions [18,19].…”

Section: Introductionmentioning

confidence: 99%

“…Since the Thakurta spacetime is a conformal transformation of the Schwarzschild metric, it is now accepted that its redshift radii points to the co-moving radii of the event horizon of BH [16,18,19]. By considering asymptotic behavior of the gravitational lagrangian (Ricci scalar), one can classify the Thakurta BH and its extension to the charged BH into the same class of solutions [18,19]. The Thakurta spacetime sustains an inward flow, which leads to an increase in the mass of BH [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…By considering asymptotic behavior of the gravitational lagrangian (Ricci scalar), one can classify the Thakurta BH and its extension to the charged BH into the same class of solutions [18,19]. The Thakurta spacetime sustains an inward flow, which leads to an increase in the mass of BH [18][19][20]. This ingoing flow comes from the back-reaction effect and can be neglected in a low density background [20].…”

Section: Introductionmentioning

confidence: 99%

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Spherically symmetric solutions in a FRW background

Moradpour

Riazi

2015

Mod. Phys. Lett. A

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We impose perfect fluid concept along with slow expansion approximation to derive new solutions which, considering non-static spherically symmetric metrics, can be treated as Black Holes (BHs). We will refer to these solutions as Quasi BHs. Mathematical and physical features such as Killing vectors, singularities, and mass have been studied. Their horizons and thermodynamic properties have also been investigated. In addition, relationship with other related works (including McVittie's) are described

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“…As we have previously mentioned, the dark energy candidate, as the dominated fluid in the present state of the universe, is the backbone of the probable thermodynamic equilibrium of the universe [2,[4][5][6]. In fact, since the satisfaction of the thermodynamic equilibrium conditions in the current stage of the universe expansion is not impossible [2,[4][5][6][29][30][31][32], it is not also unlikely to define the thermodynamic pressure for at least the dark energy component as the dominated fluid in the current state of the universe. In thermodynamics, pressure is defined as…”

Section: Perfect Fluid Model Cannot Satisfy Thermodynamics and Cosmolmentioning

confidence: 99%

A note on the relations between thermodynamics, energy definitions and Friedmann equations

et al. 2017

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In what follows, we investigate the relation between the Friedmann and thermodynamic pressure equations, through solving the Friedmann and thermodynamic pressure equations simultaneously. Our investigation shows that a perfect fluid, as a suitable solution for the Friedmann equations leading to the standard modeling of the universe expansion history, cannot simultaneously satisfy the thermodynamic pressure equation and those of Friedmann. Moreover, we consider various energy definitions, such as the Komar mass, and solve the Friedmann and thermodynamic pressure equations simultaneously to get some models for dark energy. The cosmological consequences of obtained solutions are also addressed. Our results indicate that some of obtained solutions may unify the dominated fluid in both the primary inflationary and current accelerating eras into one model. In addition, by taking into account a cosmic fluid of a known equation of state, and combining it with the Friedmann and thermodynamic pressure equations, we obtain the corresponding energy of these cosmic fluids and face their limitations. Finally, we point out the cosmological features of this cosmic fluid and also study its observational constraints.

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Thermodynamic behavior and stability of Polytropic gas

Cited by 14 publications

References 32 publications

Thermodynamic descriptions of polytropic gas and its viscous type as dark energy candidates

Thermodynamic descriptions of polytropic gas and its viscous type as dark energy candidates

Spherically symmetric solutions in a FRW background

A note on the relations between thermodynamics, energy definitions and Friedmann equations

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