Vacuum fluctuations in the inflaton field driving chaotic inflation with a quadratic potential give a red spectrum of primordial density perturbations, n=0.97. However angular fluctuations in an O(N)-symmetric quadratic potential have a very nearly scale-invariant spectrum, n=0.9998. We investigate the possibility that these isocurvature field perturbations could give the dominant contribution to the primordial density perturbation after inflation.
Physical Review D
- Pub Date:
- March 2006
- Particle-theory and field-theory models of the early Universe;
- High Energy Physics - Phenomenology
- 10 pages, LaTeX with RevTex, no figures