Review of Local Non-Gaussianity from Multifield Inflation

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...

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Main Authors: Christian T. Byrnes, Ki-Young Choi
Format: Article
Language:English
Published: Wiley 2010-01-01
Series:Advances in Astronomy
Online Access:http://dx.doi.org/10.1155/2010/724525
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author Christian T. Byrnes
Ki-Young Choi
author_facet Christian T. Byrnes
Ki-Young Choi
author_sort Christian T. Byrnes
collection DOAJ
description 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 fNL and the trispectrum.
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spelling doaj-art-2e9a0bc7144d47f7a40b64aff331b2102025-08-20T03:55:07ZengWileyAdvances in Astronomy1687-79691687-79772010-01-01201010.1155/2010/724525724525Review of Local Non-Gaussianity from Multifield InflationChristian T. Byrnes0Ki-Young Choi1Fakultät für Physik, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, GermanyDepartment of Physics, Pusan National University, Busan 609-735, Republic of KoreaWe 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 fNL and the trispectrum.http://dx.doi.org/10.1155/2010/724525
spellingShingle Christian T. Byrnes
Ki-Young Choi
Review of Local Non-Gaussianity from Multifield Inflation
Advances in Astronomy
title Review of Local Non-Gaussianity from Multifield Inflation
title_full Review of Local Non-Gaussianity from Multifield Inflation
title_fullStr Review of Local Non-Gaussianity from Multifield Inflation
title_full_unstemmed Review of Local Non-Gaussianity from Multifield Inflation
title_short Review of Local Non-Gaussianity from Multifield Inflation
title_sort review of local non gaussianity from multifield inflation
url http://dx.doi.org/10.1155/2010/724525
work_keys_str_mv AT christiantbyrnes reviewoflocalnongaussianityfrommultifieldinflation
AT kiyoungchoi reviewoflocalnongaussianityfrommultifieldinflation