Venue: Maths 103
Motivated theories of inflation typically involve multiple fields living on a curved space. In the last year two different papers have demonstrated how covariant perturbations are an economic way to consider how such inflationary models are perturbed about a background FRWL expansion. We have now extended this analysis for the power spectrum and bispectrum. First we demonstrate how to quantize the perturbations in the sub-horizon regime which represents an extension of the Seery-Lidsey result for multifield inflation; the field curvature leads to new rich dynamics. Second we extend the transport formalism of Mulryne, Seery and Wesley to evolve these covariant perturbations in the super-horizon epoch. Finally we give the covariant gauge transformation to obtain the curvature perturbation and thus connect with CMB observables. I may also discuss some current extensions of this work.