Spherical Subspace Potential Functional Theory

The recently introduced version of the density functional theory that employs a set of spherically symmetric densities instead of the density has a 'set-representability problem'. It is not known if a density exists for a given set of the spherically symmetric densities. This problem can be eliminated if potentials are applied instead of densities as basic variables. Now, the spherical subspace potential functional theory is established.

Automated summary

The recent version of density functional theory faces a challenge called 'set-representability problem' when using spherically symmetric densities. It is uncertain whether there exists a density for a given set of spherically symmetric densities. However, this problem can be solved by using potentials instead of densities as fundamental variables. Thus, the spherical subspace potential functional theory is developed.