Quantum fate of singularities in a dark-energy dominated universe

Bouhmadi-López, Mariam; Kiefer, Claus; Sandhöfer, Barbara; Moniz, Paulo Vargas

doi:10.1103/physrevd.79.124035

Cited by 81 publications

(87 citation statements)

References 78 publications

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“…In these works, it was concluded that once the Universe enters in a genuinely quantum phase; i.e., where coherence and entanglement effects are important, the Universe would evade a doomsdayà la rip. This applies even to the smoother version of these singular behaviours corresponding to a LSBR [41] (see also [43][44][45][46][47]). …”

Section: Introductionmentioning

confidence: 99%

Cosmological perturbations in an effective and genuinely phantom dark energy Universe

Albarran

Bouhmadi-López

Morais

2017

Physics of the Dark Universe

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We carry out an analysis of the cosmological perturbations in general relativity for three different models which are good candidates to describe the current acceleration of the Universe. These three set-ups are described classically by perfect fluids with a phantom nature and represent deviations from the most widely accepted ΛCDM model. In addition, each of the models under study induce different future singularities or abrupt events known as (i) Big Rip, (ii) Little Rip and (iii) Little Sibling of the Big Rip. Only the first one is regarded as a true singularity since it occurs at a finite cosmic time. For this reason, we refer to the others as abrupt events. With the aim to find possible footprints of this scenario in the Universe matter distribution, we not only obtain the evolution of the cosmological scalar perturbations but also calculate the matter power spectrum for each model. We have carried the perturbations in the absence of any anisotropic stress and within a phenomenological approach for the speed of sound. We constrain observationally these models using several measurements of the growth rate function, more precisely f σ8, and compare our results with the observational ones.

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Section: Introductionmentioning

confidence: 99%

Cosmological perturbations in an effective and genuinely phantom dark energy Universe

Albarran

Bouhmadi-López

Morais

2017

Physics of the Dark Universe

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“…This was a counterexample to what was believed at the time and it was the first discovery of these types of singularity in cosmology with an explicit construction given in [3]. Sudden singularities were further studied in [4][5][6][7][8][9][10][11][12][13]. The Type IV singularity has some phenomenologically appealing applications and implications in cosmology, as was shown in [14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 83%

Constraints on singular evolution from gravitational baryogenesis

Oikonomou

2016

Int. J. Geom. Methods Mod. Phys.

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We investigate how the gravitational baryogenesis mechanism can potentially constrain the form of a Type IV singularity. Specifically, we study two different models with interesting phenomenology, that realize two distinct Type IV singularities, one occurring at the end of inflation and one during the radiation domination era or during the matter domination era. As we demonstrate, the Type IV singularities occurring at the matter domination era or during the radiation domination era are constrained by the gravitational baryogenesis, in such a way so that these do not render the baryon to entropy ratio singular. Both the cosmological models we study cannot be realized in the context of ordinary Einstein-Hilbert gravity, and hence our work can only be realized in the context of F (R) gravity and more generally in the context of modified gravity only.

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“…Among them is the big freeze singularity [40][41][42], which takes place at a finite scale factor, in a (flat) FriedmannRobertson-Walker (FRW) universe. For example the future big freeze singularity can appear in a FRW universe with a (phantom) generalized Chaplygin gas (GCG) [40].…”

Section: Classification Of the Possible Evolutional Scenarios In The mentioning

confidence: 99%

Do sewn up singularities falsify the Palatini cosmology?

et al. 2016

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We investigate further (cf. Borowiec et al. JCAP 1601(01):040, 2016) the Starobinsky cosmological model R + γ R 2 in the Palatini formalism with a Chaplygin gas and baryonic matter as a source in the context of singularities. The dynamics reduces to the 2D sewn dynamical system of a Newtonian type (a piece-wise-smooth dynamical system). We demonstrate that the presence of a sewn up freeze singularity (glued freeze type singularities) for the positive γ is, in this case, a generic feature of the early evolution of the universe. It is demonstrated that γ equal zero is a bifurcation parameter and the dynamics qualitatively changes as the γ sign is changing. On the other side for the case of negative γ instead of the big bang the sudden bounce singularity of a finite scale factor does appear and there is a generic class of bouncing solutions. While the γ > 0 is favored by data only very small values of γ parameter are allowed if we require agreement with the CDM model. From the statistical analysis of astronomical observations, we deduce that the case of only very small negative values of γ cannot be rejected. Therefore, observation data favor the universe without the ghost states ( f (R) > 0) and tachyons ( f (R) > 0).

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Quantum fate of singularities in a dark-energy dominated universe

Cited by 81 publications

References 78 publications

Cosmological perturbations in an effective and genuinely phantom dark energy Universe

Cosmological perturbations in an effective and genuinely phantom dark energy Universe

Constraints on singular evolution from gravitational baryogenesis

Do sewn up singularities falsify the Palatini cosmology?

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