Experimental validation of electron correlation models in warm dense matter
Dmitrii S. Bespalov, Ulf Zastrau, Zhandos A. Moldabekov, Thomas Gawne, Tobias Dornheim, Moyassar Meshhal, Alexis Amouretti, Michal Andrzejewski, Karen Appel, Carsten Baehtz, Erik Brambrink, Khachiwan Buakor, Carolina Camarda, David Chin, Gilbert Collins, Celine Crepisson, Adrien Descamps, Jon Eggert, Luke Fletcher, Alessandro Forte, Gianluca Gregori, Marion Harmand, Oliver S. Humphries, Hauke Hoeppner, Jonas Kuhlke, William Lynn, Julian Luetgert, Masruri Masruri, Emma M. McBride, Ryan Stewart McWilliams, Alan Augusto Sanjuan Mora, Jean-Paul Naedler, Paul Neumayer, Charlotte Palmer, Alexander Pelka, Lea Pennacchioni, Danae Polsin, Calum Prestwood, Natalia A. Pukhareva, Chongbing Qu, Divyanshu Ranjan, Ronald Redmer, Michael Roeper, Christoph Sahle, Samuel Schumacher, Jan-Patrick Schwinkendorf, Melanie J. Sieber, Madison Singleton, Ethan Smith, Christian Sternemann, Thomas Stevens, Michael Stevenson, Cornelius Strohm, Minxue Tang, Monika Toncian, Toma Toncian, Thomas Tschentscher, Sam Vinko, Justin Wark, Max Wilke, Dominik Kraus, Thomas R. Preston
公開日: 2025/9/12
Abstract
We report X-ray Thomson scattering measurements of warm dense aluminium at densities 3.75-4.5 g/cm$^3$ and a temperature of approximately 0.6 eV, performed at the HED-HiBEF instrument of the European XFEL using the DiPOLE-100X drive laser. By probing plasmon dispersion across momentum transfers $k$ = 0.99-2.57 Angstrom$^{-1}$ with high statistical fidelity, we directly test competing theories of electron dynamics under extreme conditions. Time-dependent density functional theory (TDDFT) reproduces both the observed plasmon energies and spectral shapes across the full $k$ range, whereas the random phase approximation (RPA) and static local-field-correction (LFC) models systematically overestimate the plasmon frequency, even for aluminium (a canonical uniform electron gas metal). Considering electron localisation around ions and the loss of crystalline symmetry due to liquid-state disorder, our measurements provide direct evidence that simple uniform electron gas models fail in warm dense matter and establish TDDFT as a reliable approach for electronic correlations in this regime.