Plateau heights in full configuration interaction quantum Monte Carlo for the 1D Hubbard model

The sign problem in full configuration interaction quantum Monte Carlo (FCIQMC) manifests itself in a critical population size required to correctly sample the ground state wavefunction of a quantum system. Here we reproduce plateau heights (see http://dx.doi.org/10.6084/m9.figshare.1101537 and http://dx.doi.org/10.6084/m9.figshare.1096136) for the 1D Hubbard model for a variety of simulation cells, U/t values and number of electrons. Each gzipped tarball contains a set of output files for a number of calculations for a given lattice size. plateaus_all.txt contains an estimate for the plateau height for all 3928 calculations in the tarballs and plateaus_summary.txt contains the plateau height for each unique system, averaged across multiple calculations. The CSV files contain the same information in CSV format rather than an ASCII table. The plateaus were found using the plateau_finder.py script, which uses the method described in our arxiv preprint. Note that some plateaus (especially at U=0.75) are overestimated by this method. All calculations were performed with HANDE (http://www.hande.org.uk).