Unifying attractor and non-attractor models of inflation under a single soft theorem. (arXiv:2009.03369v3 [hep-th] UPDATED)
<a href="http://arxiv.org/find/hep-th/1/au:+Bravo_R/0/1/0/all/0/1">Rafael Bravo</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Palma_G/0/1/0/all/0/1">Gonzalo A. Palma</a>

We show that the observable squeezed limit of primordial curvature
perturbations in canonical single-field inflation vanishes exactly, a result
valid to all orders in slow-roll parameters. This result relies exclusively on
the diffeomorphism invariance of canonical single-field inflation, and does not
require taking into consideration de Sitter isometries or shift symmetries of
the ultraviolet theory in which inflation is build upon. An important
consequence of our result is the conclusion that a non-attractor phase (e.g.
ultra slow-roll phase) cannot generate observable local non-Gaussianity at the
end of inflation.

We show that the observable squeezed limit of primordial curvature
perturbations in canonical single-field inflation vanishes exactly, a result
valid to all orders in slow-roll parameters. This result relies exclusively on
the diffeomorphism invariance of canonical single-field inflation, and does not
require taking into consideration de Sitter isometries or shift symmetries of
the ultraviolet theory in which inflation is build upon. An important
consequence of our result is the conclusion that a non-attractor phase (e.g.
ultra slow-roll phase) cannot generate observable local non-Gaussianity at the
end of inflation.

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