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Title: Large non-Gaussianity in multiple-field inflation

Abstract

We investigate non-Gaussianity in general multiple-field inflation using the formalism we developed in earlier papers. We use a perturbative expansion of the nonlinear equations to calculate the three-point correlator of the curvature perturbation analytically. We derive a general expression that involves only a time integral over background and linear perturbation quantities. We work out this expression explicitly for the two-field slow-roll case, and find that non-Gaussianity can be orders of magnitude larger than in the single-field case. In particular, the bispectrum divided by the square of the power spectrum can easily be of O(1-10), depending on the model. Our result also shows the explicit momentum dependence of the bispectrum. This conclusion of large non-Gaussianity is confirmed in a semianalytic investigation of a simple quadratic two-field model.

Authors:
 [1]; ;  [2]
  1. Institute for Theoretical Physics, Utrecht University, Postbus 80.195, 3508 TD Utrecht (Netherlands)
  2. Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
Publication Date:
OSTI Identifier:
20782893
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 8; Other Information: DOI: 10.1103/PhysRevD.73.083522; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COSMOLOGY; DISTURBANCES; ENERGY SPECTRA; EXPANSION; FIELD EQUATIONS; INFLATIONARY UNIVERSE; INTEGRALS; NONLINEAR PROBLEMS

Citation Formats

Rigopoulos, G.I., Shellard, E.P.S., and Tent, B.J.W. van. Large non-Gaussianity in multiple-field inflation. United States: N. p., 2006. Web. doi:10.1103/PHYSREVD.73.083522.
Rigopoulos, G.I., Shellard, E.P.S., & Tent, B.J.W. van. Large non-Gaussianity in multiple-field inflation. United States. doi:10.1103/PHYSREVD.73.083522.
Rigopoulos, G.I., Shellard, E.P.S., and Tent, B.J.W. van. Sat . "Large non-Gaussianity in multiple-field inflation". United States. doi:10.1103/PHYSREVD.73.083522.
@article{osti_20782893,
title = {Large non-Gaussianity in multiple-field inflation},
author = {Rigopoulos, G.I. and Shellard, E.P.S. and Tent, B.J.W. van},
abstractNote = {We investigate non-Gaussianity in general multiple-field inflation using the formalism we developed in earlier papers. We use a perturbative expansion of the nonlinear equations to calculate the three-point correlator of the curvature perturbation analytically. We derive a general expression that involves only a time integral over background and linear perturbation quantities. We work out this expression explicitly for the two-field slow-roll case, and find that non-Gaussianity can be orders of magnitude larger than in the single-field case. In particular, the bispectrum divided by the square of the power spectrum can easily be of O(1-10), depending on the model. Our result also shows the explicit momentum dependence of the bispectrum. This conclusion of large non-Gaussianity is confirmed in a semianalytic investigation of a simple quadratic two-field model.},
doi = {10.1103/PHYSREVD.73.083522},
journal = {Physical Review. D, Particles Fields},
number = 8,
volume = 73,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}