Reviving chaotic inflation with fermion production: a SUGRA model

Reviving chaotic inflation with fermion production: a SUGRA model
Lorenzo Sorbo, UMass Amherst
Very old picture of Lorenzo Sorbo
Date and time: Tue, Sep 28, 2021 - 2:30pm
Location: LGRT 1033
Category: ACFI Seminar

Processes of particle production during inflation can increase the amplitude of the scalar metric perturbations. We show that such a mechanism can naturally arise in supergravity models where an axion-like field drives large field inflation. In this class of models one generally expects instanton-like corrections to the superpotential. We show, by deriving the equations of motion in models of supergravity with a stabilizer, that such corrections generate an interaction between the inflaton and its superpartner. This inflaton-inflatino interaction term is rapidly oscillating, and can lead to copious production of inflatinos during inflation, filling the Fermi sphere up to momenta much larger than the Hubble parameter. In their turn, those fermions source inflaton fluctuations, increasing their amplitude, and effectively lowering the tensor-to-scalar ratio for the model. This allows, in particular, to bring the model where the inflaton potential is quadratic (plus negligibly small instanton corrections) to agree with all existing observations.