Detecting a small perturbation through its non-Gaussianity
Abstract
A highly non-gaussian cosmological perturbation with a flat spectrum has unusual stochastic properties. We show that they depend on the size of the box within which the perturbation is defined, but that for a typical observer the parameters defining the perturbation `run' to compensate for any change in the box size. Focusing on the primordial curvature perturbation, we show that an un-correlated gaussian-squared component is bounded at around the 10% level by the WMAP bound on the bispectrum, and we show that a competitive bound may follow from the trispectrum when it too is bounded by WMAP. Similar considerations apply to a highly non-gaussian isocurvature perturbation.
Cite
@article{arxiv.astro-ph/0504046,
title = {Detecting a small perturbation through its non-Gaussianity},
author = {Lotfi Boubekeur and David. H. Lyth},
journal= {arXiv preprint arXiv:astro-ph/0504046},
year = {2011}
}
Comments
4 pages, revtex4, No figures. Minor changes. More discussion on the trispectrum and logarithmic scale dependence