Small Field Inflation and the Spectral Index

Abstract

It is sometimes stated that $n_s=0.98$ in hybrid inflation; sometimes that it predicts $n_s>1$. A number of authors have consider aspects of Planck scale corrections and argued that they affect these predictions. Here we consider these systematically, describing the situations which can yield $n_s=0.96$, and the extent to which this result requires additional tuning.

Comments: 12 pages, 1 figure