On the initial conditions for inflation with plateau potentials: the $R+R^2$ (super)gravity case

Understand

We discuss the initial conditions problem for inflation driven by the vacuum energy of a plateau potential, and in particular the Starobinsky inflation.

• We show that the supergravity embedding of the $R+R^2$ theory naturally decreases the size of the acausal homogeneity, required for the low-scale inflation to occur, thanks to the presence of the dynamical pure supergravitational "auxiliary" fields.
• We examine the evolution of the $R+R^2$ fields within a FLRW Universe.
• We also find a dependence of the initial conditions problem on the background spatial curvature.