Reconstructing a<i>f</i>(<i>R</i>) theory from the α-Attractors

Miranda, Tays; Fabris, J. C.; Piattella, Oliver F.

doi:10.1088/1475-7516/2017/09/041

Cited by 39 publications

(35 citation statements)

References 49 publications

(62 reference statements)

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“…Other investigations include the use of α-attractors for dark matter [12], and the relation of α-attractors with f (R) gravity, extending the original connection of α-attractors with Starobinsky R 2 gravity [13], e.g. [14,15].…”

Section: Introductionmentioning

confidence: 99%

Dark energy from α-attractors: phenomenology and observational constraints

García-García

Linder

Ruiz‐Lapuente

et al. 2018

J. Cosmol. Astropart. Phys.

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The possibility of linking inflation and late cosmic accelerated expansion using the α-attractor models has received increasing attention due to their physical motivation. In the early universe, α-attractors provide an inflationary mechanism compatible with Planck satellite CMB observations and predictive for future gravitational wave CMB modes. Additionally α-attractors can be written as quintessence models with a potential that connects a power law regime with a plateau or uplifted exponential, allowing a late cosmic accelerated expansion that can mimic behavior near a cosmological constant. In this paper we study a generalized dark energy α-attractor model. We thoroughly investigate its phenomenology, including the role of all model parameters and the possibility of large-scale tachyonic instability clustering. We verify the relation that 1 + w ∼ 1/α (while the gravitational wave power r ∼ α) so these models predict that a signature should appear in either the primordial B-modes or in late time deviation from a cosmological constant. We constrain the model parameters with current datasets, including the cosmic microwave background (Planck 2015 angular power spectrum, polarization and lensing), baryon acoustic oscillations (BOSS DR12) and supernovae (Pantheon compressed). Our results show that expansion histories close to a cosmological constant exist in large regions of the parameter space, not requiring a fine-tuning of the parameters or initial conditions.

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Section: Introductionmentioning

confidence: 99%

Dark energy from α-attractors: phenomenology and observational constraints

García-García

Linder

Ruiz‐Lapuente

et al. 2018

J. Cosmol. Astropart. Phys.

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“…As it was shown in [15], the viable range for β, determined from the Planck 2015 constraints on n s and r, is 0.1 < β < 0.9. As in the Starobinsky case, expressed by Eq.…”

Section: )mentioning

confidence: 87%

“…which it is of the same order of the tensor-to-scalar ratio. As a second case, we consider the β-model [15], which is a f (R) approximated reconstruction of the α-Attractors: 20) where σ = (1 − β) 2 /3M 2 . We notice that when β = 0 we recover the Starobinsky model modified by a constant in the linear term and when β = 1 we recover GR.…”

Section: )mentioning

confidence: 99%

Generic slow-roll and non-gaussianity parameters in f(R) theories

Miranda

Escamilla-Rivera

Piattella

et al. 2019

J. Cosmol. Astropart. Phys.

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In this paper we establish formulae for the inflationary slow-roll parameters , η and ζ as functions of the Ricci scalar R for f (R) theories of gravity. As examples, we present the analytic and numerical solutions of , η and ζ as functions of the number of e-folds N in two important instances: for the Starobinsky model and for a f (R) reconstruction of the α-Attractors. The highlight of our proposal is to rewrite the slow-roll parameters in terms of f (R), which allows to find directly n s , r, α s and f equil NL as functions of R itself. We obtain that both models indicate a small contribution to the non-Gaussianity parameters, which are in good agreement with current observational constraints.

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“…To confirm this, we consider the quadratic potential We numerically evolve Eqs. (12) and (13) with (15). The results are presented in figure 5.…”

Section: Evolution Equations and Attractorsmentioning

confidence: 99%

Observational constraints on the generalized α attractor model

Shahalam

Myrzakulov

Myrzakul

et al. 2018

Int. J. Mod. Phys. D

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We study the generalized α attractor model in the context of the late time cosmic acceleration. The model interpolates between the scaling freezing and thawing dark energy models. In the slow roll region, the original potential is modified whereas the modification ceases in the asymptotic region and the effective potential behaves as the quadratic one. In our setting, the field rolls slowly around the present epoch and mimics the scaling behavior in the future. We obtain observational constraints on the model parameters by using an integrated data base (SN+Hubble+BAO+CMB).

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Reconstructing af(R) theory from the α-Attractors

Cited by 39 publications

References 49 publications

Dark energy from α-attractors: phenomenology and observational constraints

Dark energy from α-attractors: phenomenology and observational constraints

Generic slow-roll and non-gaussianity parameters in f(R) theories

Observational constraints on the generalized α attractor model

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