A Note on Holographic Renormalization of Probe D-Branes
A great deal of progress has been recently made in the study of holography for non-conformal branes. Considering the near-horizon limit of backgrounds generated by such branes, we discuss the holographic renormalization of probe D-branes in these geometries. More specifically, we discuss in some detail systems with a codimension-one defect. For this class of systems, the mode which describes the probe branes wrapping a maximal 2-sphere in the transverse space behaves like a free massive scalar propagating in a higher-dimensional (asymptotically) AdS_{q+1}-space. The counterterms needed are then the ones of a free massive scalar in asymptotically AdS_{q+1}. The original problem can be recovered by compactifying the AdS-space on a torus and finally performing the analytic continuation of q to the value of interest, which can be fractional. We compute the one-point correlator for the operator dual to the embedding function. We finally comment on holographic renormalization in the more general cases of codimension-k defects (k=0, 1, 2). In all the cases the embedding function exhibits the behaviour of a free massive scalar in an AdS-space and, therefore, the procedure outlined before can be straightforwardly applied. Our analysis completes the discussion of holographic renormalization of probe D-branes started by Karch, O'Bannon and Skenderis.