We study several aspects of the recently introduced fixed-phase spin-orbitdiffusion Monte Carlo (FPSODMC) method, in particular, its relation to thefixed-node method and its potential use as a general approach for electronicstructure calculations. We illustrate constructions of spinor-based wavefunctions with the full space-spin symmetry without assigning up or down spinlabels to particular electrons, effectively "complexifying" even ordinaryreal-valued wave functions. Interestingly, with proper choice of the simulationparameters and spin variables, such fixed-phase calculations enable one toreach also the fixed-node limit. The fixed-phase solution provides astraightforward interpretation as the lowest bosonic state in a given effectivepotential generated by the many-body approximate phase. In addition, thedivergences present at real wave function nodes are smoothed out to lowerdimensionality, decreasing thus the variation of sampled quantities and makingthe sampling also more straightforward. We illustrate some of these propertieson calculations of selected first-row systems that recover the fixed-noderesults with quantitatively similar levels of the corresponding biases. At thesame time, the fixed-phase approach opens new possibilities for more generaltrial wave functions with further opportunities for increasing accuracy inpractical calculations.
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