Accurate Exchange-Correlation Energies for the Warm Dense Electron Gas.
The density matrix quantum Monte Carlo (DMQMC) method is used to sample exact-on-average N-body density matrices for uniform electron gas systems of up to 10^{124} matrix elements via a stochastic solution of the Bloch equation. The results of these calculations resolve a current debate over the accuracy of the data used to parametrize finite-temperature density functionals. Exchange-correlation energies calculated using the real-space restricted path-integral formalism and the k-space configuration path-integral formalism disagree by up to ∼10% at certain reduced temperatures T/T_{F}≤0.5 and densities r_{s}≤1. Our calculations confirm the accuracy of the configuration path-integral Monte Carlo results available at high density and bridge the gap to lower densities, providing trustworthy data in the regime typical of planetary interiors and solids subject to laser irradiation. We demonstrate that the DMQMC method can calculate free energies directly and present exact free energies for T/T_{F}≥1 and r_{s}≤2.
Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
Fionn D
FD
Malone
University Chemical Laboratory, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom.|Max Planck Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart 70569, Germany.
N S
NS
Blunt
Institute for Theoretical Physics, ETH Zürich, Wolfgang Pauli Strasse 27, 8093 Zürich, Switzerland.
Ethan W
EW
Brown
Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
D K K
DK
Lee
Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.|Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
J S
JS
Spencer
Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
W M C
WM
Foulkes
Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.|Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
James J
JJ
Shepherd