A critical assessment of models of pair-interactions and screening used in analyzing recent warm-dense matter (WDM) experiments

TL;DR

This paper critically evaluates common theoretical models used in analyzing warm-dense matter experiments, demonstrating that simplified models like Yukawa screening and core-repulsion are misleading, and employs advanced density-functional methods for accurate analysis.

Contribution

The study introduces a comprehensive, accurate density-functional approach to analyze WDM experiments, avoiding oversimplified models and confirming results with electronic-structure calculations.

Findings

Yukawa and core-repulsion models are misleading for WDM analysis.

The density-functional neutral-pseudoatom model provides accurate structure factors and physical properties.

Advanced methods improve interpretation of ultra-fast laser experiment data.

Abstract

Ultra-fast laser experiments yield increasingly reliable data on warm-dense matter (WDM), but rely on entrenched simplistic theoretical models. We re-analyze two topical experiments, avoiding (i) {\it ad hoc} core-repulsion models, (ii) "Yukawa screening" models and (iii) electron-ion equilibrium assumptions. An accurate, rapid density-functional neutral-pseudoatom model coupled to a hyper-netted-chain (HNC) equation with a bridge term is used to compute structure factors, X-Ray scattering, compressibility, phonons and resistivity. Electronic-structure codes are used to confirm the calculations. The Yukawa and core-repulsion models are shown to be misleading.