Non-linear isocurvature perturbations and non-Gaussianities

By D. Langlois, F. Vernizzi, D. Wands. 2008

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We study non-linear primordial adiabatic and isocurvature perturbations and their non-Gaussianity. After giving a general formulation in the context of an extended δN formalism, we analyse in detail two illustrative examples. The first is a mixed curvaton–inflaton scenario in which fluctuations of both the inflaton and a curvaton (a light isocurvature field during inflation) contribute to the primordial density perturbation. The second example is that of double inflation involving two decoupled massive scalar fields during inflation. In the mixed curvaton–inflaton scenario we find that the bispectrum of primordial isocurvature perturbations may be large and comparable to the bispectrum of adiabatic curvature perturbations.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Oceanography

View Paper: https://www.semanticscholar.org/paper/95ee5bdda3642b5b7d6c08ae00b544b6eb9f2b28

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Citations in the corpus

Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “Even though negligible in the two-point function, their presence could be detected in the three-point function of the primordial curvature and isocurvature perturbations and their cross-correlations, as studied in [660, 727].”
Review of local non-Gaussianity from multi-field inflation (2010, methodology): “density perturbation studying the isocurvature perturbation in [62].”
Planck 2015 results. XVII. Constraints on primordial non-Gaussianity (2015, unknown): “…bispectra because of the cross-correlation between isocurvature and adiabatic perturbations (Komatsu 2002; Bartolo et al. 2002; Komatsu et al. 2005; Kawasaki et al. 2008, 2009; Langlois et al. 2008; Hikage et al. 2009; Langlois & Lepidi 2011; Langlois & van Tent 2011, 2012; Kawakami et al. 2012).”
Planck 2018 results. IX. Constraints on primordial non-Gaussianity (2019, background): “…cross-correlation between isocurvature and adiabatic perturbations (Komatsu 2002; Bartolo et al. 2002; Komatsu et al. 2005; Kawasaki et al. 2008; Langlois et al. 2008; Kawasaki et al. 2009; Hikage et al. 2009; Langlois & Lepidi 2011; Langlois & van Tent 2011; Kawakami et al. 2012; Langlois &…”
Production of purely gravitational dark matter (2018, background): “3) should be replaced with Rχ× O(1) and non-Gaussianity of the isocurvature perturbation becomes important [31, 32].”