Non-Gaussian perturbations from multi-field inflation
Abstract
We show how the primordial bispectrum of density perturbations from inflation may be characterised in terms of manifestly gauge-invariant cosmological perturbations at second order. The primordial metric perturbation, zeta, describing the perturbed expansion of uniform-density hypersurfaces on large scales is related to scalar field perturbations on unperturbed (spatially-flat) hypersurfaces at first- and second-order. The bispectrum of the metric perturbation is thus composed of (i) a local contribution due to the second-order gauge-transformation, and (ii) the instrinsic bispectrum of the field perturbations on spatially flat hypersurfaces. We generalise previous results to allow for scale-dependence of the scalar field power spectra and correlations that can develop between fields on super-Hubble scales.
Cite
@article{arxiv.astro-ph/0509719,
title = {Non-Gaussian perturbations from multi-field inflation},
author = {Laura E. Allen and Sujata Gupta and David Wands},
journal= {arXiv preprint arXiv:astro-ph/0509719},
year = {2009}
}
Comments
11 pages, RevTex; minor changes to text; conclusions unchanged; version to appear in JCAP