The Trispectrum in the Effective Theory of Inflation with Galilean symmetry

Understand

We calculate the trispectrum of curvature perturbations for a model of inflation endowed with Galilean symmetry at the level of the fluctuations around an FRW background.

• Such a model has been shown to posses desirable properties such as unitarity (up to a certain scale) and non-renormalization of the leading operators, all of which point towards the reasonable assumption that a full theory whose fluctuations reproduce the one here might exist as well as be stable and predictive.
• The cubic curvature fluctuations of this model produce quite distinct signatures at the level of the bispectrum.
• Our analysis shows how this holds true at higher order in perturbations.