Tensor-to-Scalar Ratio in Eddington-inspired Born-Infeld Inflation
  We investigate the scalar perturbation of the inflation model driven by a massive-scalar field in Eddington-inspired Born-Infeld gravity. We focus on the perturbation at the attractor stage in which the first and the second slow-roll conditions are satisfied. The scalar perturbation exhibits the corrections to the chaotic inflation model in general relativity. We find that the tensor-to-scalar ratio becomes smaller than that of the usual chaotic inflation. 
Inyong Cho and Naveen K. Singh
gr-qc hep-th