Scalar QED in AdS

We consider scalar QED with N_f flavors in AdS _D. For D < 4 the theory is strongly-coupled in the IR. We use the spin 1 spectral representation to compute and efficiently resum the bubble diagram in AdS, in order to obtain the exact propagator of the photon at large N_f. We then apply this result to compute the boundary four-point function of the charged operators at leading order in 1/N_f and exactly in the coupling, both in the Coulomb and in the Higgs phase. In the first case a conserved current is exchanged in the four-point function, while in the second case the current is absent and there is a pattern of double-trace scaling dimension analogous to a resonance in flat space. We also consider the BCFT data associated to the critical point with bulk conformal symmetry separating the two phases. Both in ordinary perturbation theory and at large N_f, in integer dimension D = 3 an IR divergence breaks the conformal symmetry on the boundary by inducing a boundary RG flow in a current-current operator.