v-representability of one-body density matrices

D. Van Neck, M. Waroquier, K. Peirs, V. Van Speybroeck
Physical Review A
64 (4), 042512


We consider low-dimensional model systems with a fixed two-body interaction and a variable (nonlocal) one-body potential. It is shown explicitly that an extended domain of allowed (N-representable) one-body density matrices cannot be generated in this way, the excluded domain depending on the two-body interaction under consideration. This stands in contrast to the behavior of the diagonal part of the density matrix.

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