Thermodynamics of nonsingular bouncing universes

Ferreira, P. Castelo; Pavón, Diego

doi:10.1140/epjc/s10052-016-3886-2

Cited by 22 publications

(15 citation statements)

References 42 publications

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“…Both instances correspond to small scale systems. Although different authors assumed it to be in order to constrain the evolution of cosmological models (see, e.g., [5] and references therein), as far as we know, the validity of the said law at large (i.e., cosmic) scales has not been explored as yet. The main purpose of this work is to fill this gap.…”

Section: Introductionmentioning

confidence: 99%

Strategies to Ascertain the Sign of the Spatial Curvature

Ferreira

Pavón

2016

Universe

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Abstract:The second law of thermodynamics, in the presence of gravity, is known to hold at small scales, as in the case of black holes and self-gravitating radiation spheres. Using the Friedmann-Lemaître-Robertson-Walker metric and the history of the Hubble factor, we argue that this law also holds at cosmological scales. Based on this, we study the connection between the deceleration parameter and the spatial curvature of the metric, Ω k , and set limits on the latter, valid for any homogeneous and isotropic cosmological model. Likewise, we devise strategies to determine the sign of the spatial curvature index k. Finally, assuming the lambda cold dark matter model is correct, we find that the acceleration of the cosmic expansion is increasing today.

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Section: Introductionmentioning

confidence: 99%

Strategies to Ascertain the Sign of the Spatial Curvature

Ferreira

Pavón

2016

Universe

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“…The total entropy is sum of horizon entropy (S h ) and the matter (inside the horizon) entropy (S in ) i.e., For an evolving universe it is prudent to consider the entropy of dynamical apparent horizon rather than teleological event horizon. Entropy of the apparent horizon is given by the relation [21][22][23],…”

Section: Compliance Of a Pure Quintessence With Gslmentioning

confidence: 99%

“…where A denotes the area of the apparent horizon and is related to radius of the apparent horizon (R h ) as, A = 4πR 2 h . In a spatially flat FRW space, the horizon radius R h is related to Hubble parameter [21,22,24] as,…”

Section: Compliance Of a Pure Quintessence With Gslmentioning

confidence: 99%

Thawing and freezing quintessence models: a thermodynamic consideration

2019

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Thawing and freezing quintessence models are compared thermodynamically. Both of them are found to disobey the Generalized Second Law of Thermodynamics. However, for freezing models, there is still a scope as this breakdown occurs in the past, deep inside the radiation dominated era, when a standard scalar field model with a pressureless matter is not a correct description of the matter content. The thawing model has a pathological breakdown in terms of thermodynamics in a finite future.

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“…Based on the Hubble expansion history, Pavón (2014) suggested that the entropy of the Universe tends to some maximum value. Interestingly different cosmological models such as nonsingular bouncing Universes, modified gravity theories and the Universes whose expansion is dominated by matter or by phantom fields do not tend to a state of maximum entropy whereas the ΛCDM model does (Radicella & Pavón 2012;Mimoso & Pavón 2013;Ferreira & Pavón 2016).…”

Section: Introductionmentioning

confidence: 99%

Does information entropy play a role in the expansion and acceleration of the Universe?

Pandey

2017

Monthly Notices of the Royal Astronomical Society: Letters

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We propose an interpretation of the expansion and acceleration of the Universe from an information theoretic perspective. We obtain the time evolution of the configuration entropy of the mass distribution in a static Universe and show that the process of gravitational instability leads to a rapid dissipation of configuration entropy during the growth of the density fluctuations making such a Universe entropically unfavourable. We find that in an expanding Universe, the configuration entropy rate is governed by the expansion rate of the Universe and the growth rate of density fluctuations. The configuration entropy rate becomes smaller but still remains negative in a matter dominated Universe and eventually becomes zero at some future time in a Λ dominated Universe. The configuration entropy may have a connection to the dark energy and possibly plays a driving role in the current accelerating expansion of the Universe leading the Universe to its maximum entropy configuration.

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Thermodynamics of nonsingular bouncing universes

Cited by 22 publications

References 42 publications

Strategies to Ascertain the Sign of the Spatial Curvature

Strategies to Ascertain the Sign of the Spatial Curvature

Thawing and freezing quintessence models: a thermodynamic consideration

Does information entropy play a role in the expansion and acceleration of the Universe?

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