Ab initio path-integral Monte Carlo results for the one-particle spectral function of the warm dense electron gas

We compute quasi-exact \emph{ab initio} path-integral Monte Carlo results for the Matsubara Green’s function of the uniform electron gas (UEG) at finite temperature over a broad range of coupling strengths ($r_s=1,\dots ,10)$. This allows us to present approximation-free results for the static self-energy ${\mathrm{\Sigma }}_{\mathrm{\infty }}(p)$ and spectral function $A(p,\omega )$, and to benchmark previous approximate results for the UEG. In addition, our work opens up intriguing avenues to study the single-particle spectrum and density of states of real warm dense matter systems based on truly first principles.