@article{rasch_hu_mitas_2014, title={Communication: Fixed-node errors in quantum Monte Carlo: Interplay of electron density and node nonlinearities}, volume={140}, number={4}, journal={Journal of Chemical Physics}, author={Rasch, K. M. and Hu, S. M. and Mitas, L.}, year={2014} }
@article{kulahlioglu_rasch_hu_mitas_2014, title={Density dependence of fixed-node errors in diffusion quantum Monte Carlo: Triplet pair correlations}, volume={591}, ISSN={["1873-4448"]}, DOI={10.1016/j.cplett.2013.11.033}, abstractNote={Abstract We analyze trial wave function fixed-node errors for a three-electron fully spin-polarized atomic systems with varying atomic number Z . The fully spin-polarized state 4 S ( 1 s 2 s 3 s ) is the lowest quadruplet with S -symmetry and even parity and it is nearly-degenerate with the 4 S ( 1 s 2 p 3 p ) state. We find significant fixed-node errors proportional to Z at the Hartree–Fock level while the two-configuration wave function leads to nearly exact energies. This broadly agrees with our analogous study on Be-like atoms so that the dependence of fixed-node errors on density appears to be similar in both spin-polarized and unpolarized atomic systems.}, journal={CHEMICAL PHYSICS LETTERS}, author={Kulahlioglu, Adem H. and Rasch, Kevin and Hu, Shuming and Mitas, Lubos}, year={2014}, month={Jan}, pages={170–174} }
@inproceedings{hu_rasch_mitas_2012, title={Many-body nodal hypersurface and domain averages for correlated wave functions}, volume={1094}, booktitle={Advances in quantum monte carlo}, author={Hu, S. M. and Rasch, K. and Mitas, L.}, year={2012}, pages={77–87} }
@article{kolorenc_hu_mitas_2010, title={Wave functions for quantum Monte Carlo calculations in solids: Orbitals from density functional theory with hybrid exchange-correlation functionals}, volume={82}, ISSN={["1098-0121"]}, DOI={10.1103/physrevb.82.115108}, abstractNote={We investigate how the fixed-node diffusion Monte Carlo energy of solids depends on single-particle orbitals used in Slater--Jastrow wave functions. We demonstrate that the dependence can be significant, in particular in the case of 3d transition-metal compounds, which we adopt as examples. We illustrate how exchange-correlation functionals with variable exact-exchange component can be exploited to reduce the fixed-node errors. On the basis of these results we argue that the fixed-node quantum Monte Carlo provides a variational approach for optimization of effective hamiltonians with parameters.}, number={11}, journal={PHYSICAL REVIEW B}, author={Kolorenc, Jindrich and Hu, Shuming and Mitas, Lubos}, year={2010}, month={Sep} }