Ab initio path integral Monte Carlo study of the 2D uniform electron liquid at finite temperatures

Tobias Dornheim; Fotios Kalkavouras; Paul Hamann; Zhandos A. Moldabekov; Jan Vorberger; Panagiotis Tolias

Ab initio path integral Monte Carlo study of the 2D uniform electron liquid at finite temperatures

Quantum Gases 2026-07-13 v1

Authors: Tobias Dornheim , Fotios Kalkavouras , Paul Hamann , Zhandos A. Moldabekov , Jan Vorberger , Panagiotis Tolias

Abstract

We present extensive \emph{ab initio} path integral Monte Carlo (PIMC) simulations of the two-dimensional uniform electron gas (2DEG), covering a broad range of density parameters $r_s=0.1,\dots,50$ and temperatures $\Theta=k_\textnormal{B}T/E_\textnormal{Fermi}=0.5,\dots,16$ . This allows us to analyze various structural, linear density response and spectral properties. We find clear evidence of a \emph{roton-type} feature in the dynamic structure factor at strong coupling and intermediate wavenumbers. We also benchmark novel dielectric theory implementations for the 2DEG~[Kalkavouras \emph{et al.}~arXiv:2601.14989] for structural and spectral properties across the liquid phase diagram. The PIMC results can be used to benchmark existing theories and approximations, and guide the development of new methodologies.

Keywords

path integral Monte Carlo uniform electron gas 2DEG dynamic structure factor roton finite temperature ab initio

Cite

@article{arxiv.2607.11406,
  title  = {Ab initio path integral Monte Carlo study of the 2D uniform electron liquid at finite temperatures},
  author = {Tobias Dornheim and Fotios Kalkavouras and Paul Hamann and Zhandos A. Moldabekov and Jan Vorberger and Panagiotis Tolias},
  journal= {arXiv preprint arXiv:2607.11406},
  year   = {2026}
}