Higher-Curvature Corrections and Tensor Modes
  Higher-curvature corrections to the effective gravitational action may leave
signatures in the spectrum of primordial tensor perturbations if the
inflationary energy scale is sufficiently high. In this paper we further
investigate the effects of a coupling of the Inflaton field to higher-curvature
tensors in models with a minimal breaking of conformal symmetry. We show that
an observable violation of the tensor consistency relation from
higher-curvature tensors implies also a relatively large running of the tensor
tilt, enhanced even by some order of magnitude with respect to the standard
slow roll case. This may leave signatures in the tensor two-point function that
we could test to recognize higher-curvature effects, above all if they are
translated into a blue tilted spectrum visible by future Gravitational Wave
experiments. Exploiting current cosmic microwave background and gravitational
wave data we also derive constraints on the inflationary parameters, inferring
that large higher-curvature corrections seem to be disfavored.
