Thermal fluctuations of dark matter in bouncing cosmology

In this paper, we point out thermodynamical description of ghost dark energy (GDE) and its generalization to the early universe. Thereinafter, we find expressions for the entropy changes of these dark energy (DE) candidates. In addition, considering thermal fluctuations, thermodynamics of the DE component interacting with a dark matter (DM) sector is addressed. We will also find the effects of considering the coincidence problem on the mutual interaction between the dark sectors, and thus the equation of state parameter of DE. Finally, we derive a relation between the mutual interaction of the dark components of the universe, accelerated with the either GDE or its generalization, and the thermodynamic fluctuations.

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Pre-Big-Bang Black-Hole Remnants and Past Low Entropy

Universe ◽

10.3390/universe4110129 ◽

2018 ◽

Vol 4 (11) ◽

pp. 129 ◽

Cited By ~ 2

Author(s):

Carlo Rovelli ◽

Francesca Vidotto

Keyword(s):

Black Hole ◽

Dark Matter ◽

Big Bang ◽

The State ◽

Arrow Of Time ◽

Bouncing Cosmology ◽

Hypothetical Scenario ◽

The Big Bang ◽

Low Entropy

Dark matter could be composed by black-hole remnants formed before the big-bang era in a bouncing cosmology. This hypothetical scenario has implications on the issue of the arrow of time: it upsets a common attribution of past low entropy to the state of the geometry and suggests a possible realisation of the perspectival interpretation of past low entropy.

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Anisotropic universe and thermodynamical illustration of the interacting generalized ghost dark energy

Canadian Journal of Physics ◽

10.1139/cjp-2015-0821 ◽

2016 ◽

Vol 94 (6) ◽

pp. 540-547 ◽

Cited By ~ 1

Author(s):

Vahid Fayaz

Keyword(s):

Dark Matter ◽

Dark Energy ◽

Apparent Horizon ◽

Thermal Fluctuations ◽

Coupling Constants ◽

Mutual Interaction ◽

Anisotropic Universe ◽

Type I ◽

Isotropic Universe ◽

Ghost Dark Energy

We describe the thermodynamical interpretation of the interaction between ghost and general ghost dark energy (GDE) and dark matter in a non-isotropic universe. At first, the presence or absence of interaction between GDE and dark matter in both flat and non-isotropic geometry is discussed. Then, this investigation was extended to the non-interaction and interacting general ghost dark energy in a non-isotropic universe. Additionally, the probable relationship between the thermal fluctuations of the system and the assumed mutual interaction is investigated. Finally, we show that if one wants to solve the coincidence problem by using this mutual interaction, then the coupling constants of the interaction will be constrained. We extend our procedure to the first law of thermodynamics at the apparent horizon of a Bianchi type I universe, and assuming that the associated entropy with apparent horizon has a quantum corrected relation. Our study shows that, with the local equilibrium assumption, the generalized second law of thermodynamics is fulfilled in a region enclosed by the apparent horizon.

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