Quantum phantom cosmology

Dąbrowski, Mariusz P.; Kiefer, Claus; Sandhöfer, Barbara

doi:10.1103/physrevd.74.044022

Cited by 144 publications

(167 citation statements)

References 78 publications

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“…The classical singular asymptotic behaviour of these dark energy models has led to a quantum cosmological analysis of these setups [39][40][41][42]95]. 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.…”

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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“…and for the big-rip singularity occuring at large scale factor, [15]. The big-rip singularity is a singularity which the universe can encounter when it ex-pands "too rapidly" [16].…”

Section: Introductionmentioning

confidence: 99%

Quantum cosmology with a big-brake singularity

2007

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We investigate a cosmological model with a big-brake singularity in the future: while the first time derivative of the scale factor goes to zero, its second time derivative tends to minus infinity. Although we also discuss the classical version of the model in some detail, our main interest lies in its quantization. We formulate the Wheeler-DeWitt equation and derive solutions describing wave packets. We show that all such solutions vanish in the region of the classical singularity, a behaviour which we interpret as singularity avoidance. We then discuss the same situation in loop quantum cosmology. While this leads to a different factor ordering, the singularity is there avoided, too.

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“…Later on this duality was generalized into more complicated DE models, where it has been shown to exist too [166,167,168,169,170,171]. In [172,173] the authors have studied this cosmic duality and its connection to the fates of the universe, while in [174] the author has also discussed the possibility of realizing the aforementioned duality in braneworld cosmological paradigm. A common feature of these studies is that the EoS parameter does not cross −1.…”

Section: Cosmic Dualitymentioning

confidence: 99%

Quintom cosmology: Theoretical implications and observations

et al. 2010

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We review the paradigm of quintom cosmology. This scenario is motivated by the observational indications that the equation of state of dark energy across the cosmological constant boundary is mildly favored, although the data are still far from being conclusive. As a theoretical setup we introduce a no-go theorem existing in quintom cosmology, and based on it we discuss the conditions for the equation of state of dark energy realizing the quintom scenario. The simplest quintom model can be achieved by introducing two scalar fields with one being quintessence and the other phantom. Based on the double-field quintom model we perform a detailed analysis of dark energy perturbations and we discuss their effects on current observations. This type of scenarios usually suffer from a manifest problem due to the existence of a ghost degree of freedom, and thus we review various alternative realizations of the quintom paradigm. The developments in particle physics and string theory provide potential clues indicating that a quintom scenario may be obtained from scalar systems with higher derivative terms, as well as from nonscalar systems. Additionally, we construct a quintom realization in the framework of braneworld cosmology, where the cosmic acceleration and the phantom divide crossing result from the combined effects of the field evolution on the brane and the competition between four and five dimensional gravity. Finally, we study the outsets and fates of a universe in quintom cosmology. In a scenario with null energy condition violation one may obtain a bouncing solution at early times and therefore avoid the Big Bang singularity. Furthermore, if this occurs periodically, we obtain a realization of an oscillating universe. Lastly, we comment on several open issues in quintom cosmology and their connection to future investigations.

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Quantum phantom cosmology

Cited by 144 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

Quantum cosmology with a big-brake singularity

Quintom cosmology: Theoretical implications and observations

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