Quantum Field Theory and Unification in AdS5

TL;DR

This work analyzes gauge coupling unification in a warped 5D AdS5 two-brane setup by placing gauge fields in the bulk and employing a holographically consistent regularization. It develops the mixed-position/momentum-space formalism for 5D propagators, derives the necessary Feynman rules, and uses the background-field method to compute the 1-loop beta function incorporating KK modes and A5/ghost contributions. The authors show that the zero-mode coupling runs logarithmically with energy, allowing high-scale unification under suitable cutoffs and KK spectra, thereby reconciling unification with the hierarchy-suppressing warp factor. The framework provides a controlled, AdS/CFT–informed approach to threshold corrections and radion dynamics, highlighting conditions under which unification remains viable in warped extra-dimensional theories.

Abstract

We consider gauge bosons in the bulk of AdS5 in a two-brane theory that addresses the hierarchy problem. We show such a theory can be consistent with gauge coupling unification at a high scale. We discuss subtleties in this calculation and show how to regulate consistently in a bounded AdS5 background. Our regularization is guided by the holographic dual of the calculation.