Nongaussianity in the microwave background radiation is bound to play a key role in giving us clues about the physics of the very early Universe. However, the associated calculations, at second and even third order in perturbation theory, tend to be complicated to the point of obscuring simple underlying physical processes. In this note, we present a simple analytic procedure for approximating the nonlinearity parameters fNL and gNL for cyclic models in which the cosmological perturbations are generated via the entropic mechanism. Our approach is quick, physically transparent, and agrees well with the results of numerical calculations.
|Original language||English (US)|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|State||Published - Nov 24 2009|
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)