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

Abstract

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 modelling 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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References in corpus (15)

• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• The Clustering of the SDSS DR7 Main Galaxy Sample I: A 4 per cent Distance Measure at z=0.15
• Thermodynamical Properties of Apparent Horizon in Warped DGP Braneworld
• Deep Connection Between Thermodynamics and Gravity in Gauss-Bonnet Braneworld
• Friedmann Equations from Entropic Force
• Improved Constraints on the Acceleration History of the Universe and the Properties of the Dark Energy
• Implications, consequences and interpretations of generalized entropy in the cosmological setups
• Unified Dark Matter Scalar Field Models
• The universe dominated by the extended Chaplygin gas
• Considerations on the thermal equilibrium between matter and the cosmic horizon
• Unification of inflation, dark energy, and dark matter within the Salam-Sezgin cosmological model
• The quark gluon plasma equation of state and the expansion of the early Universe
• Utility of observational Hubble parameter data on dark energy evolution
• From the Komar Mass and Entropic Force Scenarios to the Einstein Field Equations on the Ads Brane
• The van der Waals fluid and its role in cosmology

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• Ideal gas with a varying (negative absolute) temperature: An alternative to dark energy?
• Implications of maximum acceleration on dynamics