Groth Simon, Dornheim Tobias, Sjostrom Travis, Malone Fionn D, Foulkes W M C, Bonitz Michael
Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany.
Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Phys Rev Lett. 2017 Sep 29;119(13):135001. doi: 10.1103/PhysRevLett.119.135001. Epub 2017 Sep 28.
In a recent Letter [T. Dornheim et al., Phys. Rev. Lett. 117, 156403 (2016)PRLTAO0031-900710.1103/PhysRevLett.117.156403], we presented the first quantum Monte Carlo (QMC) results for 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 θ=k_{B}T/E_{F}=0.5 and (ii) 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 completely ab initio exchange-correlation free energy functional; the accuracy achieved is an unprecedented ∼0.3%. This also allows us to quantify the accuracy and systematic errors of various previous approximate functionals.
在最近的一篇快报[T. 多恩海姆等人，《物理评论快报》117, 156403 (2016)PRLTAO0031 - 900710.1103/PhysRevLett.117.156403]中，我们给出了热力学极限下热致密电子气的首个量子蒙特卡罗（QMC）结果。然而，由于缺乏（i）在θ = k_BT / E_F = 0.5以下的精确QMC结果以及（ii）不同于顺磁情况的自旋极化的QMC结果，关于密度、温度和自旋极化的交换关联自由能的完整参数化仍然无法实现。在此我们克服了这两个剩余的限制。通过缩小与基态的差距并针对不同的自旋极化进行广泛的QMC模拟，我们能够获得首个完全从头算的交换关联自由能泛函；所达到的精度是前所未有的约0.3%。这也使我们能够量化各种先前近似泛函的精度和系统误差。
