Gauge invariant regularization in the AdS/CFT correspondence and ghost D-branes

A field theoretic understanding of how the radial direction in the AdS/CFT correspondence plays the role of a gauge invariant measure of energy scale has long been missing. In SU(N) Yang–Mills, a realization of a gauge invariant cutoff has been achieved by embedding the theory in spontaneously broken SU(N|N) gauge theory. With the recent discovery of ghost D-branes an AdS/CFT correspondence version of this scheme is now possible. We show that a very simple construction precisely ties the two pictures together providing a concrete understanding of the radial RG flow on the field theory side