paper

Detecting a small perturbation through its non-Gaussianity

arXiv:astro-ph/0504046 · doi:10.1103/PhysRevD.73.021301

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.

4 pages, revtex4, No figures. Minor changes. More discussion on the trispectrum and logarithmic scale dependence

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