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arXiv · 1004.5363

Non-gaussianity and Statistical Anisotropy in Cosmological Inflationary Models

Cesar A. Valenzuela-Toledo
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Abstract

We study the statistical descriptors for some cosmological inflationary models that allow us to get large levels of non-gaussianity and violations of statistical isotropy. Basically, we study two different class of models: a model that include only scalar field perturbations, specifically a subclass of small-field slow-roll models of inflation with canonical kinetic terms, and models that admit both vector and scalar field perturbations. We study the former to show that it is possible to attain very high, including observable, values for the levels of non-gaussianity f_{NL} and \tao_{NL} in the bispectrum B_ζ and trispectrum T_ζ of the primordial curvature perturbation ζ respectively. Such a result is obtained by taking care of loop corrections in the spectrum P_ζ, the bispectrum B_ζ and the trispectrum T_ζ. Sizeable values for f_{NL} and \tao_{NL} arise even if ζ is generated during inflation. For the latter we study the spectrum P_ζ, bispectrum B_ζ and trispectrum $T_ζ of the primordial curvature perturbation when ζ is generated by scalar and vector field perturbations. The tree-level and one-loop contributions from vector field perturbations are worked out considering the possibility that the one-loop contributions may be dominant over the tree level terms. The levels of non-gaussianity f_{NL} and \tao_{NL}, are calculated and related to the level of statistical anisotropy in the power spectrum, g_ζ. For very small amounts of statistical anisotropy in the power spectrum, the levels of non-gaussianity may be very high, in some cases exceeding the current observational limit.

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Cesar A. Valenzuela-Toledo. 2010-04-29. Non-gaussianity and Statistical Anisotropy in Cosmological Inflationary Models. https://arxiv.org/abs/1004.5363

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