Dynamical mean-field theory of resonating-valence-bond antiferromagnets

We propose a theory of the spin dynamics of frustrated quantum antiferromagnets, which is based on an effective action for a plaquette embedded in a self-consistent bath. This approach, supplemented by a low-energy projection, is applied to the Kagomé antiferromagnet. We find that a spin-liquid regime extends to very low energy, in which local correlation functions have a slow decay in time, well described by power-law behavior and omega/T scaling of the response function: chi(") (omega) is proportional to omega(-alpha)F (omega/T).