Inflaton Condensate Fragmentation: Analytical Conditions and Application to \(\alpha\)-Attractor Models

Abstract

We study the stability of an inflaton condensate in the presence of an attractive inflaton self-interaction, in order to determine analytical conditions on the self-interaction couplings under which the condensate undergoes fragmentation. As an application of our results, we consider the stability of the inflaton condensate in E-model and T-model \(\alpha\)-attractor inflation. We show that the stability of the condensate depends upon the value of \(\alpha\). For the E-model with \(q = 1\), the condensate is unstable for \(\alpha \lesssim 0.16\), while for the T-model with \(q = 1\) it is unstable for \(\alpha \lesssim 10^{-4}\). In these cases it is expected that inflation will be followed by an oscillon-dominated era.