Bayesian evidence for α-attractor dark energy models

Cedeño, Francisco X. Linares; Montiel, Ariadna; Hidalgo, Juan Carlos; Germán, Gabriel

doi:10.1088/1475-7516/2019/08/002

Cited by 26 publications

(6 citation statements)

References 107 publications

(124 reference statements)

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“…In the context of dark energy, α-attractor models with an energy scale far below the one used in inflation were considered in Refs. [46][47][48]. An interesting connection between dark energy and inflation for α-attractor models has also been investigated in Refs.…”

Section: Introductionmentioning

confidence: 97%

Unified framework for early dark energy from α -attractors

et al. 2020

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One of the most appealing approaches to ease the Hubble tension is the inclusion of an early dark energy (EDE) component that adds energy to the Universe in a narrow redshift window around the time of recombination and dilutes faster than radiation afterwards. In this paper, we analyze EDE in the framework of α-attractor models. As is well known, the success in alleviating the Hubble tension crucially depends on the shape of the energy injection. We show how different types of energy injections can be obtained, thanks to the freedom in choosing the functional form of the potential inspired by α-attractor models. To confirm our intuition, we perform a Markov-chain Monte Carlo analysis for three representative cases and find indeed that H 0 is significantly larger than in ΛCDM, like in other EDE models. Unlike axion-driven EDE models with a super-Planckian decay constant, the curvature of the potential in the EDE models required by the data is natural in the context of recent theoretical developments in α-attractors.

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Section: Introductionmentioning

confidence: 97%

Unified framework for early dark energy from α -attractors

et al. 2020

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“…The equation of motion (2.1) can be solved directly, see for instance the study about the so-called αattractors in[88,89], where one finds a detailed study of the background and perturbed quantities corresponding to, among others, different SFDM models. It is known, however, that such direct approach is difficult, in numerical terms, because of the rapid oscillations of the SF at late times.…”

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confidence: 99%

Scalar field dark matter with a cosh potential, revisited

Ureña–López

2019

J. Cosmol. Astropart. Phys.

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Dark matter models in which the constituent particle is an ultra-light boson have become part of the mainstream discussion in cosmology and astrophysics. At the classical level, the models are represented by the dynamics of a (real or complex) scalar field endowed with a potential that contains its self-interactions, and for this reason are generically known as scalar field dark matter models. Here, we revisit the properties of such a model with a cosh potential and compare it with other known examples in the literature. Within the cosmological context, the self-interaction in the potential induces a radiation-like behavior at early times of the scalar field density, which is followed by a proper matter-like behavior at the onset of rapid field oscillations around the minimum of the potential. The solutions are found by numerical means, and from them we obtain information about the cosmological observables up to the level of linear density perturbations. We also study the general properties of selfgravitating objects in the non-relativistic limit and determine the role in them of the selfinteraction obtained from the cosh potential. An overall conclusion is that, for the range of values in its parameters allowed by different constraints, a cosh potential behaves almost indistinguishable from the simpler quadratic one, which also means that the two models suffer the same tight constraints from cosmological and astrophysical observations.

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“…These combine to form the posterior probability distribution P(θ |D, M), which is the distribution sampled in our MCMC analysis. As noted by [60], the use of model selection criteria such as the Bayesian Information Criterion (BIC), Akaike Information Criterion (AIC) and Deviance Information Criterion (DIC) are not strictly Bayesian as they do not take into account the prior information. We therefore use the Bayes factor as our model comparison tool, defined in the following way:…”

Section: Tablementioning

confidence: 99%

Latest evidence for a late time vacuum–geodesic CDM interaction

Hogg

Bruni

Crittenden

et al. 2020

Physics of the Dark Universe

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We perform a reconstruction of the coupling function between vacuum energy and geodesic cold dark matter using the latest observational data. We bin the interaction in seventeen redshift bins but use a correlation prior to prevent rapid, unphysical oscillations in the coupling function. This prior also serves to eliminate any dependence of the reconstruction on the binning method. We use two different forms of the correlation prior, finding that both give similar results for the reconstruction of the dark matter-dark energy interaction. Calculating the Bayes factor for each case, we find no meaningful evidence for deviation from the null interacting case, i.e. ΛCDM, in our reconstruction.

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Bayesian evidence for α-attractor dark energy models

Cited by 26 publications

References 107 publications

Unified framework for early dark energy from α -attractors

Unified framework for early dark energy from α -attractors

Scalar field dark matter with a cosh potential, revisited

Latest evidence for a late time vacuum–geodesic CDM interaction

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