Temperature dependence of the optical spectral weight in the cuprates: role of electron correlations

We compare calculations based on the dynamical mean-field theory of the Hubbard model with the infrared spectral weight W; T of La2xSrxCuO4 and other cuprates. Without using fitting parameters we show that most of the anomalies found in W; T with respect to normal metals, including the existence of two different energy scales for the doping and the T dependence of W; T, can be ascribed to strong correlation effects.