Understanding and improving the efficiency of full configuration interaction quantum Monte Carlo
Abstract
Within full configuration interaction quantum Monte Carlo, we investigate how the statistical error behaves as a function of the parameters which control the stochastic sampling. We define the inefficiency as a measure of the statistical error per particle sampling the space and per time step and show there is a sizeable parameter regime where this is minimised. We find that this inefficiency increases sublinearly with Hilbert space size and can be reduced by localising the canonical HartreeFock molecular orbitals, suggesting that the choice of basis impacts the method beyond that of the sign problem.
 Publication:

Journal of Chemical Physics
 Pub Date:
 March 2016
 DOI:
 10.1063/1.4943113
 arXiv:
 arXiv:1601.00865
 Bibcode:
 2016JChPh.144i4110V
 Keywords:

 Physics  Chemical Physics
 EPrint:
 7 pages, 4 figures, Supplementary material available as 'Ancillary Files'