Starobinsky-like inflationary models as avatars of no-scale supergravity

Models of cosmological inflation resembling the Starobinsky R+R² model emerge naturally among the effective potentials derived from no-scale SU(N,1)/SU(N) × U(1) supergravity when N > 1. We display several examples in the SU(2,1)/SU(2) × U(1) case, in which the inflaton may be identified with either a modulus field or a matter field. We discuss how the modulus field may be stabilized in models in which a matter field plays the rôle of the inflaton. We also discuss models that generalize the Starobinsky model but display different relations between the tilt in the spectrum of scalar density perturbations, n_s, the tensor-to-scalar ratio, r, and the number of e-folds, N_*. Finally, we discuss how such models can be probed by present and future CMB experiments.