Non-canonical two-field inflation to order $ξ^2$
In non-canonical two-field inflation models, deviations from the canonical model can be captured by a parameter $ξ$. We show this parameter is usually one half of the slow-roll order and analytically calculate the primordial power spectra accurate to order $ξ^2$. The super-horizon perturbations are studied with an improved method, which gives a correction of order $ξ^2$. Three typical examples demonstrate that our analytical formulae of power spectra fit well with numerical simulation.
gr-qc↗