• Generalized density-functional theory: Conquering theN-representability problem with exact functionals for the electron pair density and the second-order reduced density matrix

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      https://www.ias.ac.in/article/fulltext/jcsc/117/05/0507-0514

    • Keywords

       

      Density-functional theory; N-representability problem; electron pair density

    • Abstract

       

      Using the constrained search and Legendre-transform formalisms, one can derive “generalized” density-functional theories, in which the fundamental variable is either the electron pair density or the second-order reduced density matrix. In both approaches, theN-representability problem is solved by the functional, and the variational principle is with respect to all pair densities (density matrices) that are nonnegative and appropriately normalized. The Legendre-transform formulation provides a lower bound on the constrained-search functional. Noting that experience in density-functional and density-matrix theories suggests that it is easier to approximate functionals than it is to approximate the set ofN-representable densities sheds some light on the significance of this work.

    • Author Affiliations

       

      Paul W Ayers1 Mel Levy2 3

      1. Department of Chemistry, McMaster University, Hamilton, Ontario - L8S 4M1, Canada
      2. Department of Physics, North Carolina A&T University, Greensboro, NC - 27411, USA
      3. Department of Chemistry, Tulane University, New Orleans, LA - 70118, USA
    • Dates

       
  • Journal of Chemical Sciences | News

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