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arXiv · 1210.2965

CMB Power Asymmetry from Non-Gaussian Modulation

Fabian Schmidt·Lam Hui
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Abstract

Non-Gaussianity in the inflationary perturbations can couple observable scales to modes of much longer wavelength (even superhorizon), leaving as a signature a large-angle modulation of the observed cosmic microwave background (CMB) power spectrum. This provides an alternative origin for a power asymmetry which is otherwise often ascribed to a breaking of statistical isotropy. The non-Gaussian modulation effect can be significant even for typical ~10^{-5} perturbations, while respecting current constraints on non-Gaussianity, if the squeezed limit of the bispectrum is sufficiently infrared divergent. Just such a strongly infrared-divergent bispectrum has been claimed for inflation models with a non-Bunch-Davies initial state, for instance. Upper limits on the observed CMB power asymmetry place stringent constraints on the duration of inflation in such models.

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Fabian Schmidt, Lam Hui. 2012-12-14. CMB Power Asymmetry from Non-Gaussian Modulation. https://doi.org/10.1103/physrevlett.110.011301

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