The spectrum of marginally-deformed N=2 CFTs with AdS4 S-fold duals of type IIB

A holographic duality was recently established between an N = 4 non-geometric AdS(4) solution of type JIB supergravity in the so-called S-fold class, and a three-dimensional conformal field theory (CFT) defined as a limit of N = 4 super-Yang-Mills at an interface. Using gauged supergravity, the N = 2 conformal manifold (CM) of this CFT has been assessed to be two-dimensional. Here, we holographically characterise the large-N operator spectrum of the marginally-deformed CFT. We do this by, firstly, providing the algebraic structure of the complete Kaluza-Klein (KK) spectrum on the associated two-parameter family of AdS(4) solutions. And, secondly, by computing the N = 2 super-multiplet dimensions at the first few KK levels on a lattice in the CM, using new exceptional field theory techniques. Our KK analysis also allows us to establish that, at least at large N, this N = 2 CM is topologically a non-compact cylindrical Riemann surface bounded on only one side.