A smooth constant-roll to a slow-roll modular inflation transition

Abstract

In this work, we investigate how a smooth transition from a constant-roll to a slow-roll inflationary era may be realized in the context of a canonical scalar field theory. We study in some detail the dynamical evolution of the cosmological system, and we investigate whether a stable attractor exists, both numerically and analytically. We also investigate the slow-roll era and as we demonstrate, the partially compatibility of the resulting scalar theory may be achieved with the potential of the latter belonging to a class of modular inflationary potentials. The novel features of the constant-roll to slow-roll transition which we achieved are firstly that it is not compelling for the slow-roll era to last for [Formula: see text]–60 [Formula: see text]-foldings, but it may last for a smaller number of [Formula: see text]-foldings, since some [Formula: see text]-foldings may occur during the constant-roll era. Secondly, when the slow-roll era occurs after the constant-roll era, the graceful exit from inflation may occur, a feature absent in the constant-roll scenario, due to the stability properties of the final attractor in the constant-roll case.