Classical and quantum warm dense electron gas dynamic characteristics: analytic predictions

We apply a novel 9-moment variational version of the self-consistent non-perturbative method of moments to study how the temperature affects the dynamic response of the electron gas in thermodynamic equilibrium. The theoretical results are obtained with the only input being the static structure factor. Comparison is carried out with the data obtained in the random-phase and the effective static local-field (ESA) (1) approximations. A quite satisfactory agreement is achieved with the system dynamic structure factor evaluated within the ESA interpolation scheme. We analyze the system properties for the temperature values (1 ≤ T / T F ≤ 4) chosen in the range where the electron gas starts to undergo a transition from the degenerate to classical behaviour. The extension of the method to a broader range of temperatures and densities is straightforward and is left for future studies. Nevertheless, we demonstrate a systematic way to investigate the gradual transition from degenerate to classical systems.