Cyclic universe with an inflationary phase from a cosmological model with real gas quintessence

Ivanov, Rossen I.; Prodanov, Emil M.

doi:10.1103/physrevd.86.083536

Cited by 11 publications

(35 citation statements)

References 29 publications

(44 reference statements)

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“…This situation changed with the discovery of accelerated expansion of the Universe in 1998., which opened an era of extensive research on modified gravity theories. In fact, cosmological solutions with cyclic properties are not rarely encountered in different theoretical frameworks of modified gravity [46][47][48][49][50][51][52], and there are also numerous works analyzing the construction of bouncing cosmologies in modified gravity [53][54][55][56][57][58][59][60][61][62].…”

Section: Models Of Cyclic Cosmologymentioning

confidence: 99%

Cyclic cosmology in modified gravity

Pavlović

Sossich

2017

Phys. Rev. D

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In this work we propose a new general model of eternal cyclic Universe. We start from the assumption that quantum gravity corrections can be effectively accounted by the addition of higher order curvature terms in the Lagrangian density for gravity. It is also taken into account that coefficients associated with these curvature corrections will in general be dependent on a curvature regime. We therewith assume no new ingredients, such as extra dimensions, new scalar fields, phantom energy or special space-time geometries. Evolution of the Universe in this framework is studied and general properties of each phase of the cycle -cosmological bounce, low curvature (ΛCDM) phase, destruction of bounded systems and contracting phase -are analysed in detail. Focusing on some simple special cases, we obtain analytical and numerical solutions for the each phase confirming our analysis.

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Section: Models Of Cyclic Cosmologymentioning

confidence: 99%

Cyclic cosmology in modified gravity

Pavlović

Sossich

2017

Phys. Rev. D

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“…Other studies pertaining to the cylic universe, which are not reviewed here, include: 5D dynamics of general braneworld models [174], past-shrinking cycles that spend more time in an entropy conserving Hagedorn phase [175], a cyclic magnetic universe [176,177], phantom accretion onto black holes [178], deformed Hořava-Lifshitz gravity [179], a string-inspired model via a scalartachyon coupling and a contribution from curvature in a closed universe [180], cosmological hysteresis [181], Finsler-like gravity theories constructed on tangent bundles to Lorentz manifolds [182], a combination of cyclic and inflationary phases with quintessence [183] and a cyclic model with a chameleon field [184], among others [185][186][187].…”

Section: B Ekpyrotic and Cyclic Scenariosmentioning

confidence: 99%

A critical review of classical bouncing cosmologies

2015

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Given the proliferation of bouncing models in recent years, we gather and critically assess these proposals in a comprehensive review. The PLANCK data shows an unmistakably red, quasi scaleinvariant, purely adiabatic primordial power spectrum and no primary non-Gaussianities. While these observations are consistent with inflationary predictions, bouncing cosmologies aspire to provide an alternative framework to explain them. Such models face many problems, both of the purely theoretical kind, such as the necessity of violating the NEC and instabilities, and at the cosmological application level, as exemplified by the possible presence of shear. We provide a pedagogical introduction to these problems and also assess the fitness of different proposals with respect to the data. For example, many models predict a slightly blue spectrum and must be fine-tuned to generate a red spectral index; as a side effect, large non-Gaussianities often result.We highlight several promising attempts to violate the NEC without introducing dangerous instabilities at the classical and/or quantum level. If primordial gravitational waves are observed, certain bouncing cosmologies, such as the cyclic scenario, are in trouble, while others remain valid. We conclude that, while most bouncing cosmologies are far from providing an alternative to the inflationary paradigm, a handful of interesting proposals have surfaced, which warrant further research. The constraints and lessons learned as laid out in this review might guide future research.

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“…Differentiation of (7) with respect to time and substitution into it of:Ḣ from (6),ρ from (12), andρ d from (13), leads to an identity. Using equation (7), the dust energy density can be expressed as ρ d = 3H 2 − ρ and eliminated from (8) so that the following dynamical equation holds [17,18]:…”

Section: The Set-upmentioning

confidence: 99%

“…The quintessential scheme can also be achieved without the usually discussed scalar fields. Alternative quintessence models introduce real gas equations of state [13,14,15,16,17,18]. General Relativity with a perfect fluid of any type can be recast equivalently as a modified gravity theory [19,20].…”

Section: Introductionmentioning

confidence: 99%

“…The Baum-Frampton model [32,33] is based on phantom cosmology. There are many other studies on cyclic Universes -see, for example, [17,18,26,34]. In this study, a quintessence cosmological model, based on the most general real gas is presented as a nonlinear dynamical system of three variables -the number density, the Hubble parameter and the temperature.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dynamical analysis of an n−H−T cosmological quintessence real gas model with a general equation of state

Ivanov¹,

Prodanov²

2018

Int. J. Mod. Phys. A

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The cosmological dynamics of a quintessence model based on real gas with general equation of state is presented within the framework of a three-dimensional dynamical system describing the time evolution of the number density, the Hubble parameter, and the temperature. Two global first integrals are found and examples for gas with virial expansion and van der Waals gas are presented. The van der Waals system is completely integrable. In addition to the unbounded trajectories, stemming from the presence of the conserved quantities, stable periodic solutions (closed orbits) also exist under certain conditions and these represent models of a cyclic Universe. The cyclic solutions exhibit regions characterised by inflation and deflation, while the open trajectories are characterised by inflation in a "fly-by" near an unstable critical point.

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Cyclic universe with an inflationary phase from a cosmological model with real gas quintessence

Cited by 11 publications

References 29 publications

Cyclic cosmology in modified gravity

Cyclic cosmology in modified gravity

A critical review of classical bouncing cosmologies

Dynamical analysis of an n−H−T cosmological quintessence real gas model with a general equation of state

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