The tilted-plane structure of the energy of finite quantum systems

Fuente: arXiv
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Autores principales: Burgess, Andrew C., Linscott, Edward, O'Regan, David D.
Formato: Preprint
Publicado: 2023
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author Burgess, Andrew C.
Linscott, Edward
O'Regan, David D.
author_facet Burgess, Andrew C.
Linscott, Edward
O'Regan, David D.
contents The piecewise linearity condition on the total energy with respect to the total magnetization of finite quantum systems is derived, using the infinite-separation-limit technique. This generalizes the well-known constancy condition, related to static correlation error, in approximate density functional theory (DFT). The magnetic analog of the DFT Koopmans' theorem is also derived. Moving to fractional electron count, the tilted plane condition is derived, lifting certain assumptions in previous works. This generalization of the flat plane condition characterizes the total energy surface of a finite system for all values of electron count N and magnetization M. This result is used in combination with tabulated spectroscopic data to show the flat plane-structure of the oxygen atom, among others. We find that derivative discontinuities with respect to electron count sometimes occur at non-integer values. A diverse set of tilted plane structures is shown to occur in d-orbital subspaces, depending on chemical coordination. General occupancy-based total-energy expressions are demonstrated thereby to be necessarily dependent on the symmetry-imposed degeneracies.
format Preprint
id arxiv_https___arxiv_org_abs_2307_16003
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle The tilted-plane structure of the energy of finite quantum systems
Burgess, Andrew C.
Linscott, Edward
O'Regan, David D.
Strongly Correlated Electrons
Chemical Physics
Computational Physics
The piecewise linearity condition on the total energy with respect to the total magnetization of finite quantum systems is derived, using the infinite-separation-limit technique. This generalizes the well-known constancy condition, related to static correlation error, in approximate density functional theory (DFT). The magnetic analog of the DFT Koopmans' theorem is also derived. Moving to fractional electron count, the tilted plane condition is derived, lifting certain assumptions in previous works. This generalization of the flat plane condition characterizes the total energy surface of a finite system for all values of electron count N and magnetization M. This result is used in combination with tabulated spectroscopic data to show the flat plane-structure of the oxygen atom, among others. We find that derivative discontinuities with respect to electron count sometimes occur at non-integer values. A diverse set of tilted plane structures is shown to occur in d-orbital subspaces, depending on chemical coordination. General occupancy-based total-energy expressions are demonstrated thereby to be necessarily dependent on the symmetry-imposed degeneracies.
title The tilted-plane structure of the energy of finite quantum systems
topic Strongly Correlated Electrons
Chemical Physics
Computational Physics
url https://arxiv.org/abs/2307.16003