Ab-initio description of warm dense matter

Warm dense matter (WDM)---an extreme state that is characterized by extreme densities and
temperatures---has emerged as one of the most active frontiers in plasma physics and material
science. In nature, WDM occurs in astrophysical objects such as giant planet interiors and brown
dwarfs. In addition, WDM is highly important for cutting-edge technological applications such as
inertial confinement fusion and the discovery of novel materials.
In the laboratory, WDM is studied experimentally in large facilities around the globe, and new
techniques have facilitated unprecedented insights into exciting phenomena like the formation of
nano diamonds at planetary interior conditions [1]. Yet, the interpretation of these experiments
requires a reliable diagnostics based on accurate theoretical modeling, which is a notoriously
difficult task [2].
In this talk, I give an overview of recent promising developments [3] in the field of ab initio
computer simulations of WDM, which open up new avenues for the accurate description of real
materials [4]. Moreover, I show that we can extract key parameters such as the temperature of a
given sample from X-ray Thomson scattering (XRTS) measurements [5] without any models or
approximations [6].

[1] D. Kraus et al., Nature Astronomy 1, 606-611 (2017)
[2] M. Bonitz et al., Physics of Plasmas 27, 042710 (2020)
[3] T. Dornheim et al., Physics Reports 744, 1-86 (2018)
[4] M. Böhme et al., Physical Review Letters 129, 066402 (2022)
[5] R. Redmer and S. Glenzer, Reviews of Modern Physics 81, 1625 (2009)
[6] T. Dornheim et al., Nature Communications 13, 7911 (2022)