Göttingen 2025 – scientific programme

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P: Fachverband Plasmaphysik

P 11: Laser Plasmas

P 11.1: Invited Talk

Wednesday, April 2, 2025, 11:00–11:30, ZHG102

Ab initio path integral Monte Carlo simulation of warm dense matter — •Tobias Dornheim — Center for Advanced Systems Understanding (CASUS), Görlitz, Germany — Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany

Understanding matter at extreme densities, temperatures and pressures is important for the modeling of astrophysical objects (e.g. giant planet interiors) and technological applications (most notably inertial confinement fusion) alike. Yet, the intricate interplay of effects such as Coulomb coupling, quantum degeneracy, and strong thermal excitations renders the rigorous theoretical description of such warm dense matter (WDM) challenging.

Here, I present an overview of a number of recent developments in the ab initio path integral Monte Carlo (PIMC) simulation of WDM. While being computationally demanding, PIMC is exact within the given error bars and, thus, constitutes a valuable benchmark for computationally more efficient but potentially less accurate methods such as density functional theory (DFT). Moreover, these simulations open up new avenues for the interpretation of X-ray Thomson scattering (XRTS) measurements, which is a key method of diagnostics for experiments with extreme states of matter. As a practical example, we consider a recent XRTS experiment on strongly compressed beryllium carried out at the National Ignition Facility (NIF) in Livermore, for which we find a significantly lower density based on both ab initio PIMC and DFT simulations compared to previously used chemical models and radiation hydrodynamics calculations.

Keywords: Warm dense matter; X-ray Thomson scattering; Inertial confinement fusion; Path integral Monte Carlo; High energy density