Can Effective Field Theory of inflation generate large tensor-to-scalar ratio within Randall Sundrum single braneworld?

TL;DR

This paper demonstrates that within the Randall Sundrum single braneworld scenario, effective field theory of inflation can produce a large tensor-to-scalar ratio with sub-Planckian field excursions, aligning with recent observational data.

Contribution

It provides a model-independent analysis showing how high energy brane inflation can generate large tensor-to-scalar ratios without super-Planckian fields.

Findings

Large tensor-to-scalar ratio achievable with sub-Planckian inflaton excursions.

Consistency with BICEP2 and Planck observational bounds.

Theoretical constraints on brane tension and quantum gravity scale.

Abstract

In this paper my prime objective is to explain the generation of large tensor-to-scalar ratio from the single field sub-Planckian inflationary paradigm within Randall Sundrum (RS) single braneworld scenario in a model independent fashion. By explicit computation I have shown that the effective field theory prescription of brane inflation within RS single brane setup is consistent with sub- Planckian excursion of the inflaton field, which will further generate large value of tensor-to-scalar ratio, provided the energy density for inflaton degrees of freedom is high enough compared to the brane tension in high energy regime. Finally, I have mentioned the stringent theoretical constraint on positive brane tension, cut-off of the quantum gravity scale and bulk cosmological constant to get sub-Planckian field excursion along with large tensor-to-scalar ratio as recently observed by BICEP2 or at least generates the tensor-to-scalar ratio consistent with the upper bound of Planck (2013 and 2015) data and Planck+BICEP2+Keck Array joint constraint.