Primordial perturbations and non-Gaussianities in DBI and general multifield inflation
Primordial perturbations and non-Gaussianities in DBI and general multifield inflation
We study cosmological perturbations in general inflation models with multiple scalar fields and arbitrary kinetic terms, with special emphasis on the multifield extension of Dirac-Born-Infeld (DBI) inflation. We compute the second-order action governing the dynamics of linear perturbations in the most general case. Specializing to DBI inflation, we show that …