Large nonGaussianity in multiplefield inflation
Abstract
We investigate nonGaussianity in general multiplefield inflation using the formalism we developed in earlier papers. We use a perturbative expansion of the nonlinear equations to calculate the threepoint 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 twofield slowroll case, and find that nonGaussianity can be orders of magnitude larger than in the singlefield case. In particular, the bispectrum divided by the square of the power spectrum can easily be of O(110), depending on the model. Our result also shows the explicit momentum dependence of the bispectrum. This conclusion of large nonGaussianity is confirmed in a semianalytic investigation of a simple quadratic twofield model.
 Authors:
 Institute for Theoretical Physics, Utrecht University, Postbus 80.195, 3508 TD Utrecht (Netherlands)
 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 nonGaussianity in multiplefield 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 nonGaussianity in multiplefield inflation. United States. doi:10.1103/PHYSREVD.73.083522.
Rigopoulos, G.I., Shellard, E.P.S., and Tent, B.J.W. van. Sat .
"Large nonGaussianity in multiplefield inflation". United States.
doi:10.1103/PHYSREVD.73.083522.
@article{osti_20782893,
title = {Large nonGaussianity in multiplefield inflation},
author = {Rigopoulos, G.I. and Shellard, E.P.S. and Tent, B.J.W. van},
abstractNote = {We investigate nonGaussianity in general multiplefield inflation using the formalism we developed in earlier papers. We use a perturbative expansion of the nonlinear equations to calculate the threepoint 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 twofield slowroll case, and find that nonGaussianity can be orders of magnitude larger than in the singlefield case. In particular, the bispectrum divided by the square of the power spectrum can easily be of O(110), depending on the model. Our result also shows the explicit momentum dependence of the bispectrum. This conclusion of large nonGaussianity is confirmed in a semianalytic investigation of a simple quadratic twofield 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}
}

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