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(Omega,T) of La2-xSrxCuO4 and other cuprates. Without using fitting parameters we show that most of the anomalies found in W(Omega,T) with respect to normal metals, including the existence of two different energy scales for the doping and the T dependence of W(Omega,T), can be ascribed to strong correlation effects.