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arXiv · 0911.2780

Scale dependence of local f_NL

Christian T. Byrnes·Sami Nurmi·Gianmassimo Tasinato·David Wands
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Abstract

We consider possible scale-dependence of the non-linearity parameter f_NL in local and quasi-local models of non-Gaussian primordial density perturbations. In the simplest model where the primordial perturbations are a quadratic local function of a single Gaussian field then f_NL is scale-independent by construction. However scale-dependence can arise due to either a local function of more than one Gaussian field, or due to non-linear evolution of modes after horizon-exit during inflation. We show that the scale dependence of f_NL is typically first order in slow-roll. For some models this may be observable with experiments such as Planck provided that f_NL is close to the current observational bounds.

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Christian T. Byrnes, Sami Nurmi, Gianmassimo Tasinato, David Wands. 2009-11-16. Scale dependence of local f_NL. https://doi.org/10.1088/1475-7516/2010/02/034

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