English

Simple single-field inflation models with arbitrarily small tensor/scalar ratio

Cosmology and Nongalactic Astrophysics 2023-03-15 v2

Abstract

We construct a family of simple single-field inflation models consistent with Planck / BICEP Keck bounds which have a parametrically small tensor amplitude and no running of the scalar spectral index. The construction consists of a constant-roll hilltop inflaton potential with the end of inflation left as a free parameter induced by higher-order operators which become dominant late in inflation. This construction directly demonstrates that there is no lower bound on the tensor/scalar ratio for simple single-field inflation models.

Keywords

Cite

@article{arxiv.2210.05757,
  title  = {Simple single-field inflation models with arbitrarily small tensor/scalar ratio},
  author = {Nina K. Stein and William H. Kinney},
  journal= {arXiv preprint arXiv:2210.05757},
  year   = {2023}
}

Comments

14 pages, 2 figures (V3: Version submitted to JCAP)

R2 v1 2026-06-28T03:22:25.355Z