Speaker
Description
We apply the $\delta N$ formalism to study the spectrum and bispectrum of the primordial curvature perturbation $\zeta$ for the constant-roll inflation scenario where $\zeta$ is generated by vector field perturbations of a cosmic triad background field configuration. This is studied in the Friedmann-Lemaître-Robertson-Walker space-time background and in the framework of the generalized $SU(2)$ Proca theory. The latter is a variant of the generalized Proca theory where the vector field belongs to the Lie algebra of the $SU(2)$ group of global transformations under which the action is made invariant. This configuration naturally leads to consider the cosmic triad as a scalar field, the latter being the norm of the physical three-dimensional vector fields. Under this assumption, the predictions in the tensor to scalar ratio vs. spectral index plane are obtained as well as those for the level of non-gaussianity in the bispectrum, revealing the scenario would be in good agreement with the observations.
