Tuesday, September 11, 2012

1209.1663 (Massimo Boninsegni et al.)

Population size bias in Diffusion Monte Carlo    [PDF]

Massimo Boninsegni, Saverio Moroni
The size of the population of random walkers required to obtain converged estimates in DMC increases dramatically with system size. We illustrate this by comparing ground state energies of small clusters of parahydrogen (up to 48 molecules) computed by Diffusion Monte Carlo (DMC) and Path Integral Ground State (PIGS) techniques. We contend that the bias associated to a finite population of walkers is the most likely cause of quantitative numerical discrepancies between PIGS and DMC energy estimates reported in the literature, for this few-body Bose system. We discuss the viability of DMC as a general-purpose ground state technique, and argue that PIGS enjoy more favorable scaling, and represent therefore a superior option for systems of large size.
View original: http://arxiv.org/abs/1209.1663

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