Large $n$-point Functions in Resonant Inflation

Abstract: We investigate a qualitatively new regime of inflationary models with small and rapid oscillations in the potential--resonant non-Gaussianity. In contrast to the standard scenario, where most of the observable information is encoded in the power spectrum, in this regime the oscillatory signal predominantly appears in higher-order correlation functions with large $n$. This behavior emerges when the oscillation frequency $\omega$ exceeds the naive cutoff of the theory, $4\pi f$. However, as noted by Hook and Rattazzi [2306.12489], the actual cutoff is somewhat higher--though only logarithmically--when the amplitude of the oscillations is small. We identify a phenomenologically relevant window in which $n$-point functions with $3 \lesssim n \lesssim 9$ are potentially observable. In this regime, the signal exhibits 350 - 1000 oscillations per decade in $k$.