Can the thermodynamic properties of a solid be mapped onto those of a liquid?

A new approximation to the density-functional theory of classical nonuniform systems is proposed and worked out for the case of the hard-sphere solid. The theory satisfies all the formal properties of the free energy and requires only the direct correlation function of the uniform system as input. the agreement with the computer simulations of the fcc hard-sphere solid is excellent: The resulting free energies, pressures, and fluid-solid coexistence data are reproduced to within the error bars of the simulations. The theory also predicts stable bcc and sc phases which could facilitate the final nucleation into the equilibrium fcc phase.