Spin-Orbit Quantum Monte Carlo for Heavy Element Equations of State

Density functional theory (DFT) serves as a weight bearing component of ab initio equation of state construction. While it is computationally affordable and reasonably accurate, intrinsic accuracy limitations do occasionally pose problems. Quantum Monte Carlo (QMC) has a long history of benchmarking density functional theory calculations and direct equation of state determination, but has until now been limited to lower Z systems (first row of periodic table), due to its inability to accurately capture spin-orbit effects. In this talk, we will present benchmark data of Spin-Orbit QMC, whereby we are able to treat systems with non-negligible spin-orbit interactions within the trusted QMC framework. We benchmark this method on the cold-curves of iridium and gold, showing that it is more accurate than DFT. This establishes confidence in this highly accurate alternative to DFT as we work to expand the use of QMC to heavier and more complicated systems.