title: Communication: fixed-node errors in quantum Monte Carlo: interplay of electron density and node nonlinearities.
abstract: We elucidate the origin of large differences (two-fold or more) in the fixed-node errors between the first- vs second-row systems for single-configuration trial wave functions in quantum Monte Carlo calculations. This significant difference in the valence fixed-node biases is studied across a set of atoms, molecules, and also Si, C solid crystals. We show that the key features which affect the fixed-node errors are the differences in electron density and the degree of node nonlinearity. The findings reveal how the accuracy of the quantum Monte Carlo varies across a variety of systems, provide new perspectives on the origins of the fixed-node biases in calculations of molecular and condensed systems, and carry implications for pseudopotential constructions for heavy elements.
authors: Center for High Performance Simulation and Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors: Kevin M
authors: KM
authors: Rasch
authors: Center for High Performance Simulation and Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors: Shuming
authors: S
authors: Hu
authors: Center for High Performance Simulation and Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors: Lubos
authors: L
authors: Mitas