Nonlocal orbital-free noninteracting free-energy functional for warm dense matter

We have extended nonlocal orbital-free methods which enforce the correct linear response in the noninteracting uniform electron gas limit, developed at zero temperature for the kinetic energy to finite temperature for the full noninteracting free energy. Comparisons are made to the Thomas-Fermi approximation and to the orbital-dependent Kohn-Sham method. We find significantly improved agreement for the resulting functional with Kohn-Sham for a wide range of densities and temperatures. We also provide the necessary formulas for implementation in quantum molecular dynamics simulations.