Decorrelation of samples in quantum Monte Carlo calculations and scaling of autocorrelation time in Li and H2O clusters

We have investigated decorrelation of samples in quantum Monte Carlo ground-state energy calculations for large Li and H2O nanoclusters. Binning data as a way of eliminating statistical correlations, as is the common practice, is found to become increasingly impractical as the system size grows. We demonstrate nevertheless that it is possible to perform accurate energy calculations—without decorrelating samples—by exploiting the scaling of the integrated autocorrelation time as a function of the number of electrons in the system.