Effective Static Approximation: A fast and reliable tool for Warm Dense Matter Theory*

Warm dense matter (WDM) is an exotic state that occurs in astrophysical objects and is on the pathway towards inertial confinement fusion.
Yet, the theoretical description of WDM remains difficult. Here, we present an effective static approximation (ESA) for the local field correction, that combines a neural net representation [1] of G(q,0) with a consistent limit for large wave numbers q determined from the on-top pair distribution function g(0) [2]. Our scheme allows for the computation of electronic properties with high accuracy over the entire WDM regime without any additional computational cost compared to the random phase approximation. Therefore, it can be directly used for many applications such as the computation of conductivities and stopping powers, and as input for (TD-)DFT simulations, and for the interpretation of XRTS experiments.

[1] T. Dornheim et al., J. Chem. Phys. 151, 194104 (2019)
[2] T. Dornheim et al., arXiv:2008.02165 (submitted)