Precision calculation of inflation correlators at one loop

We initiate a systematic study of precision calculation of the inflation correlators at the 1-loop level, starting in this paper with bosonic 1-loop bispectrum with chemical-potential enhancement. Such 1-loop processes could lead to important cosmological collider observables but are notoriously difficult to compute due to the lack of symmetries. We attack the problem from a direct numerical approach based on the real-time Schwinger-Keldysh formalism and show full numerical results for arbitrary kinematics containing both the oscillatory signals and the backgrounds. Our results show that, while the non-oscillatory part can be one to two orders of magnitude larger, the oscillatory signal can be separated out by applying appropriate high-pass filters. We have also compared the result with analytic estimates typically adopted in the literature. While the amplitude is comparable, there is a non-negligible deviation in the frequency of the oscillatory part away from the extreme squeezed limit.

Automated summary

This paper presents a systematic study on the precision calculation of inflation correlators at the 1-loop level. It focuses on the bosonic 1-loop bispectrum with chemical-potential enhancement, which can lead to important cosmological collider observables. The study uses a direct numerical approach based on the real-time Schwinger-Keldysh formalism and shows full numerical results for arbitrary kinematics, including both the oscillatory signals and the backgrounds. The results demonstrate the possibility of separating the oscillatory signal from the non-oscillatory part using appropriate high-pass filters, and they also compare the results with analytic estimates commonly used in the literature.