Primordial non-Gaussianity from mixed inflaton-curvaton perturbations

Fonseca, José; Wands, David

doi:10.1088/1475-7516/2012/06/028

Cited by 37 publications

(53 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Following the notation of Refs. [41,42] (see also Ref. [43]), the non-Gaussianity can be written as the weighted sum of each field's contribution,…”

Section: Asymmetry From Multiple-fields Modelsmentioning

confidence: 99%

Hemispherical asymmetry and local non-Gaussianity: A consistency condition

2013

View full text Add to dashboard Cite

In this paper we provide a consistency relation between the amplitude of the hemispherical bipolar asymmetry, A, and the amplitude of the primordial non-Gaussianity in the squeezed limit, f NL , as jAj & 10 À1 f NL . We demonstrate that this consistency condition is at work for any model of inflation in which the curvature perturbations are sourced by a single light field with the Bunch-Davies initial condition, irrespective of the number of inflation fields that contribute to the background inflationary expansion. As a nontrivial example, we show that observable hemispherical asymmetry can be generated in single-field nonattractor inflationary models. We also study hemispherical asymmetry generated in the models of multiple fields inflation. We show that A is controlled by the weighted sum of non-Gaussianity contribution from each field. In particular, we show that observable hemispherical asymmetry can be generated in models in which inhomogeneities are generated from a light scalar field modulating the surface of the end of inflation.

show abstract

“…Following the notation of Refs. [41,42] (see also Ref. [43]), the non-Gaussianity can be written as the weighted sum of each field's contribution,…”

Section: Asymmetry From Multiple-fields Modelsmentioning

confidence: 99%

Hemispherical asymmetry and local non-Gaussianity: A consistency condition

2013

View full text Add to dashboard Cite

show abstract

“…Our expression reduces to that given in [44] for R ≪ 1 but is more general and remains valid for R ∼ 1 [56]. There are several terms which start from second order in R where this correction is important.…”

Section: Asymmetry In Curvaton Modelmentioning

confidence: 87%

CMB hemispherical asymmetry from non-linear isocurvature perturbations

Assadullahi

Firouzjahi

Namjoo

et al. 2015

J. Cosmol. Astropart. Phys.

Self Cite

View full text Add to dashboard Cite

We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear δN formalism to calculate the non-Gaussianity of the primordial density and isocurvature perturbations due to the presence of non-adiabatic, but approximately scale-invariant field fluctuations during multi-field inflation. This local-type nonGaussianity leads to a correlation between very long wavelength inhomogeneities, larger than our observable horizon, and smaller scale fluctuations in the radiation and matter density. Matter isocurvature perturbations contribute primarily to low CMB multipoles and hence can lead to a hemispherical asymmetry on large angular scales, with negligible asymmetry on smaller scales. In curvaton models, where the matter isocurvature perturbation is partly correlated with the primordial density perturbation, we are unable to obtain a significant asymmetry on large angular scales while respecting current observational constraints on the observed quadrupole. However in the axion model, where the matter isocurvature and primordial density perturbations are uncorrelated, we find it may be possible to obtain a significant asymmetry due to isocurvature modes on large angular scales. Such an isocurvature origin for the hemispherical asymmetry would naturally give rise to a distinctive asymmetry in the CMB polarisation on large scales.

show abstract

“…As a concrete example of a two-field model, we investigate the parameter space of the mixed inflaton curvaton scenario [31][32][33][34][35][36][37][38][39][40][41]. Here the inflaton field φ is assumed to dominate the energy density during inflation.…”

Section: A Specific Example: Mixed Inflaton and Curvaton Scenariomentioning

confidence: 99%

CMB spectral distortions in generic two-field models

Kainulainen

Leskinen

Nurmi

et al. 2017

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

Abstract. We investigate the CMB µ distortion in models where two uncorrelated sources contribute to primordial perturbations. We parameterise each source by an amplitude, tilt, running and running of the running. We perform a detailed analysis of the distribution signal as function of the model parameters, highlighting the differences compared to single-source models. As a specific example, we also investigate the mixed inflaton-curvaton scenario. We find that the µ distortion could efficiently break degeneracies of curvaton parameters especially when combined with future sensitivity of probing the tensor-to-scalar ratio r. For example, assuming bounds µ < 0.5 × 10 −8 and r < 0.01, the curvaton contribution should either vanish or the curvaton should dominate primordial perturbations and its slow-roll parameter η χ is constrained to the interval −0.007 < η χ < 0.045.

show abstract

Primordial non-Gaussianity from mixed inflaton-curvaton perturbations

Cited by 37 publications

References 62 publications

Hemispherical asymmetry and local non-Gaussianity: A consistency condition

Hemispherical asymmetry and local non-Gaussianity: A consistency condition

CMB hemispherical asymmetry from non-linear isocurvature perturbations

CMB spectral distortions in generic two-field models

Contact Info

Product

Resources

About