Models of Non-Minimal Chaotic Inflation in Supergravity

Abstract: We show how we can implement chaotic inflation in the context of supergravity by conveniently selecting the functional form of a strong enough non-minimal coupling between the inflaton and the Ricci scalar curvature. The procedure can be applied when a gauge singlet or non-singlet inflaton is coupled to another singlet superfield within linear-quadratic, trilinear or bilinear superpotential terms. The tachyonic instability occurring along the direction of the accompanying non-inflaton field can be cured by expanding the kinetic part of the frame function up to the fourth order in powers of the various fields. In the case of a gauge non-singlet inflaton, though, a conjugation symmetry has to be imposed on these terms in order for the flatness of the inflationary potential is maintained. On the other hand, some of these terms assist us to precisely reconcile the resulting scalar spectral index with the current PLANCK measurements while the other inflationary observables are in agreement with data.