skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The inflationary bispectrum with curved field-space

Abstract

We compute the covariant three-point function near horizon-crossing for a system of slowly-rolling scalar fields during an inflationary epoch, allowing for an arbitrary field-space metric. We show explicitly how to compute its subsequent evolution using a covariantized version of the separate universe or 'δN' expansion, which must be augmented by terms measuring curvature of the field-space manifold, and give the nonlinear gauge transformation to the comoving curvature perturbation. Nonlinearities induced by the field-space curvature terms are a new and potentially significant source of non-Gaussianity. We show how inflationary models with non-minimal coupling to the spacetime Ricci scalar can be accommodated within this framework. This yields a simple toolkit allowing the bispectrum to be computed in models with non-negligible field-space curvature.

Authors:
;  [1];  [2]
  1. School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London, E1 4NS (United Kingdom)
  2. Astronomy Centre, University of Sussex, Pevensey II building, Brighton, BN1 9QH (United Kingdom)
Publication Date:
OSTI Identifier:
22279888
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2012; Journal Issue: 11; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGY; COUPLING; EXPANSION; GAUGE INVARIANCE; INFLATIONARY UNIVERSE; INFLATONS; METRICS; NONLINEAR PROBLEMS; PERTURBATION THEORY; POTENTIALS; SCALAR FIELDS; SCALARS; SPACE-TIME; UNIVERSE

Citation Formats

Elliston, Joseph, Tavakol, Reza, and Seery, David, E-mail: j.elliston@qmul.ac.uk, E-mail: d.seery@sussex.ac.uk, E-mail: r.tavakol@qmul.ac.uk. The inflationary bispectrum with curved field-space. United States: N. p., 2012. Web. doi:10.1088/1475-7516/2012/11/060.
Elliston, Joseph, Tavakol, Reza, & Seery, David, E-mail: j.elliston@qmul.ac.uk, E-mail: d.seery@sussex.ac.uk, E-mail: r.tavakol@qmul.ac.uk. The inflationary bispectrum with curved field-space. United States. doi:10.1088/1475-7516/2012/11/060.
Elliston, Joseph, Tavakol, Reza, and Seery, David, E-mail: j.elliston@qmul.ac.uk, E-mail: d.seery@sussex.ac.uk, E-mail: r.tavakol@qmul.ac.uk. Thu . "The inflationary bispectrum with curved field-space". United States. doi:10.1088/1475-7516/2012/11/060.
@article{osti_22279888,
title = {The inflationary bispectrum with curved field-space},
author = {Elliston, Joseph and Tavakol, Reza and Seery, David, E-mail: j.elliston@qmul.ac.uk, E-mail: d.seery@sussex.ac.uk, E-mail: r.tavakol@qmul.ac.uk},
abstractNote = {We compute the covariant three-point function near horizon-crossing for a system of slowly-rolling scalar fields during an inflationary epoch, allowing for an arbitrary field-space metric. We show explicitly how to compute its subsequent evolution using a covariantized version of the separate universe or 'δN' expansion, which must be augmented by terms measuring curvature of the field-space manifold, and give the nonlinear gauge transformation to the comoving curvature perturbation. Nonlinearities induced by the field-space curvature terms are a new and potentially significant source of non-Gaussianity. We show how inflationary models with non-minimal coupling to the spacetime Ricci scalar can be accommodated within this framework. This yields a simple toolkit allowing the bispectrum to be computed in models with non-negligible field-space curvature.},
doi = {10.1088/1475-7516/2012/11/060},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 11,
volume = 2012,
place = {United States},
year = {2012},
month = {11}
}