A new perspective on modulus stabilization

In the original Randall-Sundrum (RS) two-brane model, the radion potential was fine-tuned to zero, leaving the extra-dimensional modulus undetermined. Goldberger and Wise (GW) introduced a stabilization mechanism by incorporating a massive bulk scalar field, leading to a radion potential with a stable minimum. In this work, we examine the impact of the intrinsic stability of the GW scalar field on the modulus stabilization procedure. To elucidate this relationship, we test the stabilization scheme across several relevant scenarios using methods of singular perturbation theory. Our analysis consistently indicates a one-to-one correspondence between the stability of the GW scalar and successful modulus stabilization. Additionally, we highlight that certain classes of GW bulk potentials demonstrate such a correspondence explicitly, and provide checks which any GW bulk potential must satisfy in order to ensure modulus stabilization.