Modeling of warm dense hydrogen via explicit real-time electron dynamics: Dynamic structure factors.

Area of Science:

• Plasma physics
• Quantum mechanics
• Computational physics

Background:

• Accurate computation of dynamic structure factor is crucial for understanding warm dense matter.
• Traditional methods often rely on approximations like Born-Oppenheimer, limiting their applicability.
• Resolving coupled electron-ion dynamics is a key challenge in warm dense hydrogen research.

Purpose of the Study:

• To present novel methods for computing the dynamic structure factor of warm dense hydrogen.
• To avoid the Born-Oppenheimer approximation and Chihara decomposition.
• To enable a unified framework for studying electron and ion dynamics.

Main Methods:

• Employing a wave-packet description to resolve electron dynamics during ion evolution.
• Developing a semiclassical method corrected by quantum constraints.
• Performing direct computation of the density response function within molecular dynamics.
• Comparing wave-packet models with PIMC and DFT-MD.

Main Results:

• The models accurately reproduce static and low-frequency behavior compared to PIMC and DFT-MD.
• High-frequency behavior shows expected limits for small and large momentum transfers.
• Characteristic flattening of plasmon dispersion observed for intermediate momentum transfers.
• Simultaneous resolution of ion-acoustic and plasmon modes achieved within a single framework.

Conclusions:

• The presented wave-packet methods offer a more complete description of warm dense hydrogen.
• These methods allow for a self-consistent treatment of collisions and screening.
• The unified framework enables simultaneous analysis of ion and free electron contributions to the spectrum.