  We present GW many-body results for ground-state properties of two simple but
very distinct families of inhomogenous systems in which traditional
implementations of density-functional theory (DFT) fail drastically. The GW
approach gives notably better results than the well-known random-phase
approximation, at a similar computational cost. These results establish GW as a
superior alternative to standard DFT schemes without the expensive numerical
effort required by quantum Monte Carlo simulations.
