Primordial density perturbation in the curvaton scenario

By D. Lyth, C. Ungarelli, D. Wands. 2002

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We analyze the primordial density perturbation when it is generated by a “curvaton” field different from the inflaton. In some cases this perturbation may have large isocurvature components, fully correlated or anticorrelated with the adiabatic component. It may also have a significant non-Gaussian component. All of these effects are calculated in a form which will enable direct comparison with current and forthcoming observational data.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/0abc8c9caf52c448760075a981ef3eb57155f8d0

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Citations in the corpus

DBI in the sky (2004, background): “inflation, and other non-trivial interactions occurring outside the horizon such as those described in [ 14 , 15, 16, 17, 18].”
Non-linear isocurvature perturbations and non-Gaussianities (2008, methodology): “If all the particle species are in full thermal equilibrium after the curvaton decays, with vanishing chemical potentials, then the primordial density perturbation must be adiabatic [ 6 , 36] and we have ζm = ζr and hence Sm = 0. However, if CDM remains decoupled from (part of) the radiation, the cu”
FIVE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE OBSERVATIONS: COSMOLOGICAL INTERPRETATION (2008, neutral): “One then finds a prediction (Lyth et al. 2003) α−1 1 − α−1 ≈ 9 ( 1 − ρcurvaton/ρtotal ρcurvaton/ρtotal )2 , (51) where ρcurvaton and ρtotal are the curvaton density and total density at the curvaton decay, respectively.”
The bispectrum of galaxies from high-redshift galaxy surveys: Primordial non-Gaussianity and non-linear galaxy bias (2007, methodology): “The local type of non-Gaussianity described by equation (2) is predicted in models such as the curvaton scenario (Lyth et al. 2003), models with inhomogeneous reheating (Dvali et al. 2004b,a), multiple field inflationary models (Bernardeau & Uzan 2002) or generically in models where the…”
Scale-dependent bias induced by local non-Gaussianity: a comparison to N-body simulations (2008, background): “While single inflaton scenarios predict fNL much less than unity, multi-field inflation models can generate fNL ≫ 1 (Linde & Mukhanov 1997; Lyth et al. 2003; Creminelli 2003; Dvali et al. 2004; Zaldarriaga 2004; Arkani-Hamed et al. 2004; Alishahiha et al. 2004).”
Planck 2015 results. XVII. Constraints on primordial non-Gaussianity (2015, positive): “2004c,b) f local NL = (5/4rD)−5rD/6−5/3, when the curvaton field has a quadratic potential (Lyth & Wands 2002; Lyth et al. 2003; Lyth & Rodriguez 2005; Malik & Lyth 2006; Sasaki et al. 2006).”
Non-Gaussianities in single field inflation and their optimal limits from the WMAP 5-year data (2009, background): “er spectrum [1, 9, 10]. We stress that the theorem of [1, 9, 10] does not apply to in ationary models where elds other than the in aton play a relevant role, either by producing entropy perturbations [6, 7, 16], or by slowing down the eld with interactions [21, 28]. These models are allowed to produ”
Non-Gaussianity in curvaton models with nearly quadratic potentials (2005, background): “gins to grow rapidly. The explanation for the behaviour of |f NL| and the physics involved is most transparent if we switch to the perturbative point of view. Using perturbation theory – 6 – one ﬁnds [11, 19] that the 1/rpart in Eq. (2.6) represents the ﬁrst order contribution while the rest is due ”
On the consistency relation of the three-point function in single-field inflation (2007, background): “The assumption of a single ’clock’ is really essential, as we will explain, and in fact there are inflationary models with more than one field that violate the consistency relation, and predict a detectable level on non-Gaussianity in the squeezed limit (see for example [5, 6]).”