Gravity on a little warped space

Abstract

We investigate the consistent inclusion of 4D Einstein gravity on a truncated slice of ${\mathrm{AdS}}_{5}$ whose bulk-gravity and UV scales are much less than the 4D Planck scale, ${M}_{*}\ensuremath{\ll}{M}_{\mathrm{Pl}}$. Such ``Little Warped Spaces'' have found phenomenological utility and can be motivated by string realizations of the Randall-Sundrum framework. Using the interval approach to brane-world gravity, we show that the inclusion of a large UV-localized Einstein-Hilbert term allows one to consistently incorporate 4D Einstein gravity into the low-energy theory. We detail the spectrum of Kaluza-Klein metric fluctuations and, in particular, examine the coupling of the little radion to matter. Furthermore, we show that Goldberger-Wise stabilization can be successfully implemented on such spaces. Our results demonstrate that realistic low-energy effective theories can be constructed on these spaces, and have relevance for existing models in the literature.