Dynamical Mean-Field Theory of Resonating Valence Bond Antiferromagnets

Abstract

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 kagome 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 a power law behaviour and $ω/T$ scaling of the response function: $χ''(ω)\propto ω^{-α}F(ω/T)$.

5 pages, 3 figures; contains some clarifications on the role of the triplet states and the triplet gap