Fermionic propagator path integral Monte Carlo of the uniform electron gas and hydrogen plasma at warm-dense matter conditions*

A significant progress has been achieved in studying exchange and correlation effects in fermionic systems using a fully anti-symmetrised density matrix propagator [1]. Ab initio results for the uniform electron gas (UEG) has been reported in a broad range of densities and temperatures~[2]. Here we extend the ideas of Refs.~[1,2] and formulate a new scheme for the grand canonical ensemble. Our simulations confirm the results of Ref.~[2] for UEG and lead to new predictions including pressure, chemical potential, pair correlation and momentum distribution functions. Furthermore, we also simulate hydrogen plasma down to temperatures 15 000 K including the transion to a molecular phase. The isotherms for the pressure and the internal energy are compared with FN-PIMC~[3] and hydrogen EOS based on DFT-MD [4]. Our results allow us to conclude on the accuracy of the fixed-node approximation depending on the degeneracy parameter.
[1] Siu A Chin, Phys. Rev. E, 031301 (2015); [2] T. Dornheim, S. Groth et al., Phys.Rep. 744, 1-86 (2018); [3] B. Milizer et al., Phys.Rev.B 84, 224109 (2011); [4] A. Becker et al., Astrophys. Jour. Supp. Series 215, 21 (2014)