Constraining Modified Gravity with Large non-Gaussianities

Understand

In writing a covariant effective action for single field inflation, one is allowed to add a Gauss-Bonnet and axion-type curvature couplings.

• These couplings represent modifications of gravity, and are the unique higher-curvature terms that lead to second order equations of motion in four dimensions.
• In this paper we study the observational consequences of such couplings for models with large non-gaussianities.
• Our focus is on the Gauss-Bonnet term.