Solution of the N-Representability Problem: Second Order Density Matrices of Finite Rank

摘要

The N-representability problem is approached by considering geminal product expansions of symmetric and antisymmetric functions. Necessary and sufficient conditions for N-representability of second order density matrices of finite rank are obtained. These conditions can be extended to give a solution to the N-representability problem for higher order density matrices. The circumstances under which a density matrix can be derived from two or more different functions are considered. (Author)