2021-08-02T16:19:41Zhttps://soar-ir.repo.nii.ac.jp/oaioai:soar-ir.repo.nii.ac.jp:000117962021-07-05T00:36:50Z1169:1170Coupling-constant expression and exact relations for the kinetic-energy functional in pair-density-functional theoryHiguchi, Katsuhiko36149Higuchi, Masahiko36150We derive the coupling-constant expression for the kinetic energy (KE) functional of the pair-density-functional theory. Such the expression can be effectively used in developing the approximate KE functional. Indeed, on the basis of this expression, we present an approximate form of the KE functional by means of the perturbation theory. Furthermore, as the first step of an alternative way of obtaining the approximate KE functional, we derive several relations and bounds for the KE functional by investigating how the KE functional changes with the nonuniform scaling, rotation, and translation of electron coordinates. Such relations and bounds can be utilized as restrictive conditions on the approximate form. Thus, the coupling-constant expression, relations and bounds obtained here provide useful tools for devising various types of the approximate KE functional that is indispensable for advancing the pair-density-functional theory.ArticlePHYSICAL REVIEW A. 85(6):062508 (2012)journal articleAMER PHYSICAL SOC2012-06-11application/pdfPHYSICAL REVIEW A685625081050-2947AA10764867https://soar-ir.repo.nii.ac.jp/record/11796/files/PhysRevA.85.062508.pdfeng10.1103/PhysRevA.85.062508http://dx.doi.org/10.1103/PhysRevA.85.062508CopyrightÂ© 2012 The American Physical Society