Higher Curvature Inflation and the Species Scale

TL;DR

This paper explores how higher curvature corrections in gravity theories influence scalar potentials and the species scale, revealing conditions for flat potentials and embedding Starobinsky inflation within the Swampland framework.

Contribution

It demonstrates the connection between higher curvature terms, the species scale, and inflationary potentials, providing a new embedding of Starobinsky inflation consistent with Swampland constraints.

Findings

Scalar potentials decay exponentially at large fields

Species scale from compactification also decays exponentially

Conditions identified for flat, plateau-like potentials

Abstract

We study the scalar potentials that arise from higher curvature corrections in general $f(R)$ theories of gravity and their connection to a dynamical species scale. Starting from general considerations in arbitrary dimensions, we show that at large field values, the scalar potential generated by an infinite series of curvature terms and the field dependent species scale arising from circle compactification both decay exponentially, in complementary ways. We identify conditions under which these two effects precisely balance out, giving rise to exponentially flat, plateau-like potentials. We additionally find a precise embedding of Starobinsky inflation consistent with the Swampland program, and we discuss possible implications the mechanism proposed could have for M and string theory.