Mixed non-Gaussianity in multiple-DBI inflation

Understand

We study a model of multiple-field DBI inflation leading to mixed form of primordial non-Gaussianity, including equilateral and local bispectrum shapes.

• We present a general formalism based on the Hamilton-Jacobi approach, allowing us to go beyond slow-roll, combining the three-point function for the fields at Hubble-exit with the non-linear evolution of super-Hubble scales.
• We are able to obtain analytic results by taking a separable Ansatz for the Hubble rate.
• We find general expressions for both the equilateral and local type non-Gaussianity parameter fNL.