Optical sum rule anomalies in the cuprates: interplay between strong correlation and electronic bandstructures

We theoretically analyze some of the anomalies of the optical sumrules in the high-temperature superconductors. In particular we address the particularly strong dependence on temperature of the sumrule in the normal state. Both electron-electron correlations and the presence of a Van-Hove singularity have been shown to enhance such a dependence. Here we consider both effects simultaneously by means of Dynamical Mean-Field Theory for a two dimensional Hubbard model with realistic parameters for different cuprates, and we find that the two effects are not cooperative, as they appear to compete one another in the region of parameters relevant for the experiments.