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Separable and non-separable multi-field inflation and large non-Gaussianity

Research output: Contribution to journalJournal article

Published

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Journal publication date5/09/2012
JournalJournal of Cosmology and Astroparticle Physics
Journal number9
Volume2012
Original languageEnglish

Abstract

In this paper we provide a general framework based on $\delta N$ formalism to estimate the cosmological observables pertaining to the cosmic microwave background radiation for non-separable potentials, and for generic \emph{end of inflation} boundary conditions. We provide analytical and numerical solutions to the relevant observables by decomposing the cosmological perturbations along the curvature and the isocurvature directions, \emph{instead of adiabatic and entropy directions}. We then study under what conditions large bi-spectrum and tri-spectrum can be generated through phase transition which ends inflation. In an illustrative example, we show that large $f_{NL}\sim {\cal O}(80)$ and $\tau_{NL}\sim {\cal O}(20000)$ can be obtained for the case of separable and non-separable inflationary potentials.

Bibliographic note

21 pages, 6 figures