title: Generalized Pauli constraints in reduced density matrix functional theory.
abstract: Functionals of the one-body reduced density matrix (1-RDM) are routinely minimized under Coleman's ensemble N-representability conditions. Recently, the topic of pure-state N-representability conditions, also known as generalized Pauli constraints, received increased attention following the discovery of a systematic way to derive them for any number of electrons and any finite dimensionality of the Hilbert space. The target of this work is to assess the potential impact of the enforcement of the pure-state conditions on the results of reduced density-matrix functional theory calculations. In particular, we examine whether the standard minimization of typical 1-RDM functionals under the ensemble N-representability conditions violates the pure-state conditions for prototype 3-electron systems. We also enforce the pure-state conditions, in addition to the ensemble ones, for the same systems and functionals and compare the correlation energies and optimal occupation numbers with those obtained by the enforcement of the ensemble conditions alone.
authors.affiliation: Peter-Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Iris
authors.initials: I
authors.lastname: Theophilou
authors.affiliation: Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Vass. Constantinou 48, GR-11635 Athens, Greece.
authors.forename: Nektarios N
authors.initials: NN
authors.lastname: Lathiotakis
authors.affiliation: Institut für Physik Martin-Luther-Universität Halle-Wittenberg, D-06120 Halle (Saale), Germany.
authors.forename: Miguel A L
authors.initials: MA
authors.lastname: Marques
authors.affiliation: Peter-Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Helbig