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arXiv · 1503.08103

The bispectrum of single-field inflationary trajectories with $c_{s} \neq 1$

Jonathan S. Horner·Carlo R. Contaldi
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Abstract

The bispectrum of single-field inflationary trajectories in which the speed of sound of the inflationary trajectories $c_s$ is constant but not equal to the speed of light $c=1$ is explored. The trajectories are generated as random realisations of the Hubble Slow-Roll (HSR) hierarchy and the bispectra are calculated using numerical techniques that extends previous work. This method allows for out-of-slow-roll models with non-trivial time dependence and arbitrarily low $c_s$. The ensembles obtained using this method yield distributions for the shape and scale-dependence of the bispectrum and their relations with the standard inflationary parameters such as scalar spectral tilt $n_s$ and tensor-to-scalar ratio $r$. The distributions demonstrate the squeezed-limit consistency relations for arbitrary single-field inflationary models.

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Jonathan S. Horner, Carlo R. Contaldi. 2015-03-27. The bispectrum of single-field inflationary trajectories with $c_{s} \neq 1$. https://arxiv.org/abs/1503.08103

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