On the initial conditions for inflation with plateau potentials: the<i>R</i>+<i>R</i>²(super)gravity case

Abstract

We discuss the initial conditions problem for inflation driven by the vacuum\nenergy of a plateau potential, and in particular the Starobinsky inflation. We\nshow that the supergravity embedding of the $R+R^2$ theory naturally decreases\nthe size of the acausal homogeneity, required for the low-scale inflation to\noccur, thanks to the presence of the dynamical pure supergravitational\n"auxiliary" fields. We examine the evolution of the $R+R^2$ fields within a\nFLRW Universe. We also find a dependence of the initial conditions problem on\nthe background spatial curvature.\n