Higher Curvature Inflation and the Species Scale

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.