Review of local non-Gaussianity from multi-field inflation

2010/02/28 by Christian T. Byrnes, Ki-Young Choi · 2 citations
Physics and Astronomy · #astro-ph.CO #hep-th

paper · pdf · doi:10.1155/2010/724525

published as Adv.Astron.2010:724525,2010 · 22 pages, 2 figures. Invited review for the special issue "Testing the Gaussianity and Statistical Isotropy of the Universe" for Advances in Astronomy. v2: Numerous references and comments added

arxiv created 2010/04/29 · arxiv updated 2015/03/13

Abstract

We review models which generate a large non-Gaussianity of the local form. We first briefly consider three models which generate the non-Gaussianity either at or after the end of inflation; the curvaton scenario, modulated (p)reheating and an inhomogeneous end of inflation. We then focus on ways of generating the non-Gaussianity during inflation. We derive general conditions which a product or sum separable potential must satisfy in order to generate a large local bispectrum during slow-roll inflation. As an application we consider two-field hybrid inflation. We then derive a formalism not based on slow roll which can be applied to models in which the slow-roll parameters become large before inflation ends. An exactly soluble two-field model is given in which this happens. Finally we also consider further non-Gaussian observables; a scale dependence of f_NL and the trispectrum.

Cited by

• Constraints on primordial non-Gaussianity from Quaia
• More fields are different: Stochastic view of multi-field inflationary scenario

Related

• Predictions for non-Gaussianity from non-local inflation
• To the study of non-Gaussianity in two-field slow-roll inflation
• Local non-Gaussianity from inflation
• Large non-Gaussianities with intermediate shapes from quasi-single-field inflation
• A geometric description of the non-Gaussianity generated at the end of multi-field inflation