Superconformal inflationary α-attractors

Abstract

Recently a broad class of superconformal inflationary models was found leading to a universal observational prediction ${n_s}=1-\frac{2}{N}$ and $r=\frac{12 }{{{N^2}}}$ [1, 2]. Here we generalize this class of models by introducing a parameter α inversely proportional to the curvature of the inflaton Kähler manifold. In the small curvature (large α) limit, the observational predictions of this class of models coincide with the predictions of generic chaotic inflation models. However, for sufficiently large curvature (small α), the predictions converge to the universal attractor regime with ${n_s}=1-\frac{2}{N}$ and $r=\alpha \frac{12 }{{{N^2}}}$, which corresponds to the part of the n _s − r plane favored by the Planck data.