Hyper non-Gaussianities in inflation with strongly non-geodesic motion

Abstract

Several recent proposals to embed inflation into high-energy physics rely on inflationary dynamics characterized by a strongly non-geodesic motion in negatively curved field space. This naturally leads to a transient instability of perturbations on sub-Hubble scales, and to their exponential amplification. Supported by first-principle numerical computations, and by the analytical insight provided by the effective field theory of inflation, we show that the bispectrum is enhanced in flattened configurations, and we argue that an analogous result holds for all higher-order correlation functions. These ``hyper non-Gaussianities'' thus provide powerful model-independent constraints on non-standard inflationary attractors motivated by the search for ultraviolet completions of inflation.

arXiv comment5 pages + appendices, 5 figures. Claim regarding the loss of perturbative control removed. New result of the enhancement of higher-order correlation functions in flattened configurations

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