Fixed-node and fixed-phase approximations and their relationship to variable spins in quantum Monte Carlo
Abstract
We compare the fixed-phase approximation with the better known, but closely related fixed-node approximation on several testing examples. We found that both approximations behave very similarly with the fixed-phase results being very close to the fixed-node method whenever nodes/phase were of high and comparable accuracy. The fixed-phase exhibited larger biases when the trial wave functions errors in the nodes/phase were intentionally driven to unrealistically large values. We also present a formalism that enables to describe wave functions with the full antisymmetry in spin-spatial degrees of freedom using our recently developed method for systems with spins as fully quantum variables. This opens new possibilities for simulations of fermionic systems in the fixed-phase approximation formalism.
Cite
@article{arxiv.1605.03813,
title = {Fixed-node and fixed-phase approximations and their relationship to variable spins in quantum Monte Carlo},
author = {Cody A. Melton and Lubos Mitas},
journal= {arXiv preprint arXiv:1605.03813},
year = {2017}
}
Comments
6 pages, 2 figures