1. Ab initio Exchange-Correlation Free Energy of the Uniform Electron Gas at Warm Dense Matter Conditions
- Author
-
Tobias Dornheim, Travis Sjostrom, Fionn D. Malone, Michael Bonitz, Simon Groth, W. M. C. Foulkes, Engineering & Physical Science Research Council (EPSRC), EPSRC, CSCS Swiss National Supercomputing Centre, Imperial College London, and Engineering and Physical Sciences Research Council
- Subjects
General Physics ,Equation of state ,Physics, Multidisciplinary ,PLASMAS ,Ab initio ,FOS: Physical sciences ,General Physics and Astronomy ,01 natural sciences ,Molecular physics ,09 Engineering ,010305 fluids & plasmas ,MONTE-CARLO ,SYSTEMS ,physics.plasm-ph ,TEMPERATURES ,Quantum mechanics ,THERMODYNAMICS ,0103 physical sciences ,cond-mat.stat-mech ,COLLECTIVE DESCRIPTION ,010306 general physics ,Condensed Matter - Statistical Mechanics ,01 Mathematical Sciences ,Spin-½ ,Physics ,Science & Technology ,02 Physical Sciences ,Statistical Mechanics (cond-mat.stat-mech) ,Spin polarization ,Warm dense matter ,EQUATION-OF-STATE ,Physics - Plasma Physics ,Plasma Physics (physics.plasm-ph) ,LIQUIDS ,GROUND-STATE ,Physical Sciences ,Thermodynamic limit ,Condensed Matter::Strongly Correlated Electrons ,Fermi gas ,Ground state ,APPROXIMATION - Abstract
In a recent Letter [T.~Dornheim \textit{et al.}, Phys. Rev. Lett. \textbf{117}, 156403 (2016)], we presented the first \textit{ab initio} quantum Monte-Carlo (QMC) results of the warm dense electron gas in the thermodynamic limit. However, a complete parametrization of the exchange-correlation free energy with respect to density, temperature, and spin polarization remained out of reach due to the absence of (i) accurate QMC results below $\theta=k_\text{B}T/E_\text{F}=0.5$ and (ii) of QMC results for spin polarizations different from the paramagnetic case. Here we overcome both remaining limitations. By closing the gap to the ground state and by performing extensive QMC simulations for different spin polarizations, we are able to obtain the first complete \textit{ab initio} exchange-correlation free energy functional; the accuracy achieved is an unprecedented $\sim 0.3\%$. This also allows us to quantify the accuracy and systematic errors of various previous approximate functionals.
- Published
- 2017