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arXiv · 0905.1781

The primordial "f_NL" non-Gaussianity, and perturbations beyond the present horizon

Jaiseung Kim·Pavel Naselsky
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Abstract

We show a primordial non-linear "f_NL" term may produce unphysically large CMB anisotropy for a red-tilted primordial power spectrum (n<1), because of coupling to primordial fluctuation on the largest scale. We consider a primordial power spectrum models of a running spectral index, and a transition at very low wavenumbers. We find that only negative running spectral index models are allowed, provided that there is no transition at a low wavenumbers (i.e. k<<1). For models of a constant spectral index, we find log(k_c/k_0)> -184, at 1 sigma level, on the transition scale of sharp cut-off models, using recent CMB and SDSS data.

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Jaiseung Kim, Pavel Naselsky. 2009-06-14. The primordial "f_NL" non-Gaussianity, and perturbations beyond the present horizon. https://doi.org/10.1103/physrevd.79.123006

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