Non-linear isocurvature perturbations and non-Gaussianities

We study non-linear primordial adiabatic and isocurvature perturbations and their non-Gaussianity. After giving a general formulation in the context of an extended $\delta N$ formalism, we analyse in detail two illustrative examples. The first is a mixed curvaton-inflaton scenario in which fluctuati...

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Bibliographic Details
Published in:Journal of cosmology and astroparticle physics 2008-12, Vol.2008 (12), p.004
Main Authors: Langlois, David, Vernizzi, Filippo, Wands, David
Format: Article
Language:English
Subjects:
Astrophysics
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
Cosmology and Extra-Galactic Astrophysics
DISTURBANCES
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
INFLATIONARY UNIVERSE
NONLINEAR PROBLEMS
Physics
SCALAR FIELDS
Sciences of the Universe
VISIBLE RADIATION
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Summary:We study non-linear primordial adiabatic and isocurvature perturbations and their non-Gaussianity. After giving a general formulation in the context of an extended $\delta N$ 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.
ISSN:1475-7516
1475-7508
1475-7516
DOI:10.1088/1475-7516/2008/12/004