English

Non-Gaussianity in single field models without slow-roll

Cosmology and Nongalactic Astrophysics 2011-05-13 v2 General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory

Abstract

We investigate non-Gaussianity in general single field models without assuming slow-roll conditions or the exact scale-invariance of the scalar power spectrum. The models considered include general single field inflation (e.g. DBI and canonical inflation) as well as bimetric models. We compute the full non-Gaussian amplitude, its size fnl, its shape, and the running with scale n_{NG}. In doing so we show that observational constraints allow significant violations of slow roll conditions and we derive explicit bounds on slow-roll parameters for fast-roll single field scenarios. A variety of new observational signatures is found for models respecting these bounds. We also explicitly construct concrete model implementations giving rise to this new phenomenology.

Keywords

Cite

@article{arxiv.1102.0275,
  title  = {Non-Gaussianity in single field models without slow-roll},
  author = {Johannes Noller and Joao Magueijo},
  journal= {arXiv preprint arXiv:1102.0275},
  year   = {2011}
}

Comments

28 pages + appendices, 6 figures, References and minor comments added in revised version

R2 v1 2026-06-21T17:20:12.574Z