  We study the dynamics of screening in photo-doped Mott insulators with
long-ranged interactions using a nonequilibrium implementation of the $GW$ plus
extended dynamical mean field theory ($GW$+EDMFT) formalism. Our study
demonstrates that the complex interplay of the injected carriers with bosonic
degrees of freedom (charge fluctuations) can result in long-lived transient
states with properties that are distinctly different from those of thermal
equilibrium states. Systems with strong nonlocal interactions are found to
exhibit a self-sustained population inversion of the doublons and holes. This
population inversion leads to low-energy antiscreening which can be detected in
time-resolved electron-energy loss spectra.
