X-ray Thomson Scattering in Warm Dense Matter without the Chihara Decomposition

Area of Science:

• Condensed Matter Physics
• Plasma Physics
• Computational Physics

Background:

• X-ray Thomson scattering is crucial for probing warm dense matter (WDM).
• Traditional models decompose electronic responses into bound, loosely bound, and free states.
• This classification becomes less accurate in the WDM regime due to high temperatures and pressures.

Purpose of the Study:

• To develop an unambiguous, first-principles calculation of the dynamic structure factor.
• To treat bound and free electrons within a unified theoretical framework, independent of the Chihara decomposition.
• To validate a novel computational approach for WDM.

Main Methods:

• Real-time, finite-temperature, time-dependent density functional theory (TDDFT) applied to WDM.
• First-principles calculations for warm dense beryllium.
• Comparison of TDDFT results with Chihara-based calculations under shock compression.

Main Results:

• TDDFT provides a unified description of electronic states in WDM.
• Calculations offer an alternative to the conventional Chihara decomposition for the dynamic structure factor.
• Significant differences observed between TDDFT and Chihara-based models for WDM.

Conclusions:

• TDDFT offers a more robust theoretical framework for studying WDM properties.
• The unified treatment of electronic states is essential for accurate WDM characterization.
• This work establishes a new computational standard for WDM research.