I was reading the review on Unconventional superconductivity by Mike Norman, towards the end (page 22) he comments two things about AdS/CMT:
"In the condensed matter context in two dimensions, one typically flows from an $AdS_4$ geometry near the boundary to an $AdS_2$ times $R_2$ one near the black hole horizon. The net result is local quantum criticality, since the spatial $R_2$ part has essentially decoupled ($AdS_2$ being dual to $CFT_1$, a conformal field theory in time). In that sense, it is similar to the Kondo problem, which is local in space and critical in time."
"Although this approach (AdS/CFT) is truly non-perturbative in nature, for most applications, the theory is essentially at the Ginzburg-Landau level. That is, one assumes a scalar field. Since it is a scalar, it should correspond to some charge 2e field, but since the theory does not explicitly invoke pairing, extra terms have to be added to the action to describe the coupling of fermions to the scalar field (i.e, to generate a Bogoliubov dispersion)."
I had hard time trying to understand the boldfaced statements, if someone can comment that'll be helpful. Thanks!