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A v0-representability issue in lattice ensemble-DFT and its signature in lattice TDDFT

Rössler, Thomas LU ; Verdozzi, Claudio LU and Almbladh, Carl-Olof LU (2018) In European Physical Journal B 91. p.1-8
Abstract
We study a small Anderson-impurity cluster using lattice density functional methods, and try to
determine the exact exchange-correlation (XC) potential via reverse engineering. In doing so we nd singlet{
triplet degenerate interacting ground states which cannot be v0-represented in an ensemble-DFT sense. We
also nd that it is possible to represent a triplet ground state as a pure state, but not the singlet. We further investigate this behavior within time-dependent density-functional theory. Starting from a v0-representableground state and entering the degeneracy region via a time-dependent perturbation, we determine via reverse-engineering the time-dependent XC potential for progressively slower perturbations. This analysis... (More)
We study a small Anderson-impurity cluster using lattice density functional methods, and try to
determine the exact exchange-correlation (XC) potential via reverse engineering. In doing so we nd singlet{
triplet degenerate interacting ground states which cannot be v0-represented in an ensemble-DFT sense. We
also nd that it is possible to represent a triplet ground state as a pure state, but not the singlet. We further investigate this behavior within time-dependent density-functional theory. Starting from a v0-representableground state and entering the degeneracy region via a time-dependent perturbation, we determine via reverse-engineering the time-dependent XC potential for progressively slower perturbations. This analysis shows that, even in a constant external eld, the XC potential must retain a time-oscillating pattern to ensure a density constant in time, a hint of the underlying representability issue in the ground state. (Less)
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publication status
published
subject
in
European Physical Journal B
volume
91
article number
219
pages
8 pages
publisher
Springer
external identifiers
  • scopus:85057242197
ISSN
1434-6028
DOI
10.1140/epjb/e2018-90205-7
language
English
LU publication?
yes
id
8f25a90c-1f3e-44da-8dde-00bbbc382762
date added to LUP
2019-05-16 10:58:02
date last changed
2020-12-01 02:13:39
@article{8f25a90c-1f3e-44da-8dde-00bbbc382762,
  abstract     = {We study a small Anderson-impurity cluster using lattice density functional methods, and try to<br/>determine the exact exchange-correlation (XC) potential via reverse engineering. In doing so we nd singlet{<br/>triplet degenerate interacting ground states which cannot be v0-represented in an ensemble-DFT sense. We<br/>also nd that it is possible to represent a triplet ground state as a pure state, but not the singlet. We further investigate this behavior within time-dependent density-functional theory. Starting from a v0-representableground state and entering the degeneracy region via a time-dependent perturbation, we determine via reverse-engineering the time-dependent XC potential for progressively slower perturbations. This analysis shows that, even in a constant external eld, the XC potential must retain a time-oscillating pattern to ensure a density constant in time, a hint of the underlying representability issue in the ground state.},
  author       = {Rössler, Thomas and Verdozzi, Claudio and Almbladh, Carl-Olof},
  issn         = {1434-6028},
  language     = {eng},
  month        = {10},
  pages        = {1--8},
  publisher    = {Springer},
  series       = {European Physical Journal B},
  title        = {A v0-representability issue in lattice ensemble-DFT and its signature in lattice TDDFT},
  url          = {http://dx.doi.org/10.1140/epjb/e2018-90205-7},
  doi          = {10.1140/epjb/e2018-90205-7},
  volume       = {91},
  year         = {2018},
}