Spectrum of Cuscuton Bounce

Understand

It has been recently shown that a cosmological bounce model based on Cuscuton gravity does not have any ghosts or curvature instabilities.

• We explore whether Cuscuton bounce can provide an alternative to inflation for generating near scale-invariant scalar perturbations.
• While a single field Cuscuton bounce generically produces a strongly blue power spectrum (for a variety of initial/boundary conditions), we demonstrate that scale invariant entropy modes can be generated in a spectator field that starts in adiabatic vacuum, and is kinetically coupled to the primary field.
• Furthermore, our solution has no singularity, nor requires an ad hoc matching condition.