Kinetically modified nonminimal chaotic inflation

Abstract

We consider supersymmetric (SUSY) and non-SUSY models of chaotic inflation based on the ϕⁿ potential with 2 ≤n ≤6 . We show that the coexistence of a nonminimal coupling to gravity f_R=1 +c_Rϕ^{n /2} with a kinetic mixing of the form f_K=c_Kf_R^m can accommodate inflationary observables favored by the Bicep2/Keck Array and Planck results for 0 ≤m ≤4 and 2.5 ×10^-4≤r_{R K}=c_R/c_K^{n /4}≤1 , where the upper limit is not imposed for n =2 . Inflation can be attained for sub-Planckian inflaton values with the corresponding effective theories retaining the perturbative unitarity up to the Planck scale.