Gravity on a Little Warped Space

TL;DR

This paper demonstrates how to incorporate 4D Einstein gravity into a truncated AdS_5 space with low bulk and UV scales, enabling realistic low-energy effective theories relevant for phenomenology.

Contribution

It shows that adding a large UV-localized Einstein-Hilbert term allows consistent inclusion of 4D gravity in Little Warped Spaces, with detailed analysis of the spectrum and stabilization.

Findings

Successful incorporation of 4D Einstein gravity in Little Warped Spaces.

Detailed spectrum analysis of Kaluza-Klein fluctuations.

Radion coupling and stabilization are feasible in these models.

Abstract

We investigate the consistent inclusion of 4D Einstein gravity on a truncated slice of AdS_5 whose bulk-gravity and UV scales are much less than the 4D Planck scale, M_* << M_{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.