Abstract
It is shown that if is the discrete density on a lattice (enclosed in a finite box) associated with a nondegenerate ground state in an external potential (i.e., is "-representable"), then the density , with arbitrary (apart from trivial constraints) and small enough, is also associated with a nondegenerate ground state in an external potential near ; i.e., is also -representable. Implications for the Hohenberg-Kohn variational principle and the Kohn-Sham equations are discussed.
- Received 8 August 1983
DOI:https://doi.org/10.1103/PhysRevLett.51.1596
©1983 American Physical Society