  Million-atom quantum simulations are in principle feasible with Orbital-Free
Density Functional Theory (OF-DFT) because the algorithms only require simple
functional minimizations with respect to the electron density function. In this
context, OF-DFT has been useful for simulations of warm dense matter, plasma,
cold metals and alloys. Unfortunately, systems as important as quantum dots and
clusters (having highly inhomogeneous electron densities) still fall outside
OF-DFT's range of applicability. In this work, we address this century old
problem by devising and implementing an accurate, transferable and universal
family of nonlocal Kinetic Energy density functionals that feature correct
asymptotics and can handle highly inhomogenous electron densities. For the
first time to date, we show that OF-DFT achieves close to chemical accuracy for
the electronic energy and reproduces the electron density to about 5\% of the
benchmark for semiconductor quantum dots and metal clusters. Therefore, this
work demonstrates that OF-DFT is no longer limited to simulations of systems
with nearly homogeneous electron density but it can venture into simulations of
clusters and quantum dots with applicability to rational design of novel
materials.
