Kinetically Modified Non-Minimal Inflation With Exponential Frame Function

TL;DR

This paper explores a class of inflationary models with exponential nonminimal coupling and kinetic mixing, demonstrating their compatibility with observational data and their theoretical consistency up to the Planck scale.

Contribution

It introduces a novel inflationary framework combining exponential frame functions with kinetic mixing, compatible with current observational constraints and embedded in supergravity.

Findings

Models fit Planck and Bicep2/Keck data

Inflation occurs at subplanckian field values

Theories remain perturbatively unitary up to the Planck scale

Abstract

We consider Supersymmetric (SUSY) and non-SUSY models of chaotic inflation based on the phi^n potential with n=2 or 4. We show that the coexistence of an exponential nonminimal coupling to gravity, fR=Exp(cR phi^p), with a kinetic mixing of the form fK=cK fR^m can accommodate inflationary observables favored by the Planck and Bicep2/Keck Array results for p=1 and 2, 1<=m<=15 and 2.6x10^(-3)<=rRK=cR/cK^(p/2)<=1, where the upper limit is not imposed for p=1. Inflation is of hilltop type and it can be attained for subplanckian inflaton values with the corresponding effective theories retaining the perturbative unitarity up to the Planck scale. The supergravity embedding of these models is achieved employing two chiral gauge singlet supefields, a monomial superpotential and several (semi)logarithmic or semipolynomial Kaehler potentials.