Features in the inflaton potential that are traversed in much less than an e-fold of the expansion can produce observably large non-Gaussianity. In these models first-order corrections to the curvature mode function evolution induce effects at second order in the slow-roll parameters that are generically greater than ∼10% and can reach order unity for order unity power spectrum features. From a complete first-order expression in generalized slow roll, we devise a computationally efficient method that is as simple to evaluate as the leading-order one and implements consistency relations in a controlled fashion. This expression matches direct numerical computation for step potential models of the dominant bispectrum configurations to better than 1% when features are small and 10% when features are order unity.
Physical Review D
- Pub Date:
- May 2012
- Particle-theory and field-theory models of the early Universe;
- Background radiations;
- Astrophysics - Cosmology and Extragalactic Astrophysics
- Phys. Rev. D 85, 103531 (2012)