Power Spectra beyond the Slow Roll Approximation in Theories with Non-Canonical Kinetic Terms

TL;DR

This paper derives analytical expressions for inflationary power spectra in multi-field, non-canonical models, emphasizing the importance of going beyond slow-roll for accurate predictions in high-precision cosmology.

Contribution

It provides the first analytical formulas for power spectra in two-field non-canonical inflation models beyond the slow-roll approximation.

Findings

Analytical expressions match numerical results across five models.

Non-canonical kinetic terms significantly affect the final power spectra.

Going beyond slow-roll is crucial for precision cosmology predictions.

Abstract

We derive analytical expressions for the power spectra at the end of inflation in theories with two inflaton fields and non-canonical kinetic terms. We find that going beyond the slow-roll approximation is necessary and that the nature of the non-canonical terms have an important impact on the final power spectra at the end of inflation. We study five models numerically and find excellent agreement with our analytical results. Our results emphasise the fact that going beyond the slow-roll approximation is important in times of high-precision data coming from cosmological observations.