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.
