<i>Ab initio</i> quantum Monte Carlo simulation of the warm dense electron gas

Abstract

Warm dense matter is one of the most active frontiers in plasma physics due to its relevance for dense astrophysical objects and for novel laboratory experiments in which matter is being strongly compressed, e.g., by high-power lasers. Its description is theoretically very challenging as it contains correlated quantum electrons at finite temperature—a system that cannot be accurately modeled by standard analytical or ground state approaches. Recently, several breakthroughs have been achieved in the field of fermionic quantum Monte Carlo simulations. First, it was shown that exact simulations of a finite model system (30…100 electrons) are possible, which avoid any simplifying approximations such as fixed nodes [Schoof et al., Phys. Rev. Lett. 115, 130402 (2015)]. Second, a novel way to accurately extrapolate these results to the thermodynamic limit was reported by Dornheim et al. [Phys. Rev. Lett. 117, 156403 (2016)]. As a result, now thermodynamic results for the warm dense electron gas are available, which have an unprecedented accuracy on the order of 0.1%. Here, we present an overview on these results and discuss limitations and future directions.