### Abstract

Moment-conserving decoupling procedures for the one-electron Green's function (electron propagator) are investigated. By analysis of one particular system (Hubbard model) it becomes clear that the momentconserving techniques so far proposed for interacting systems are all special cases of [l, 0], [2, 1], or [3, 2] Padè approximants differing only in which terms they omit, how they define self-consistency, and which operator algebra they utilize. The number of formally conserved moments appears not to be a particularly useful criterion of the accuracy of a decoupling procedure, since a two-moment scheme ( HartreeFock) may be numerically closer to the exact answer than some three-moment procedures. Use of the complete Fade approximant, as suggested by Lukman and Goscinski for the particle-hole propagator, appears to be the most consistent method.

Original language | English |
---|---|

Pages (from-to) | 3156-3161 |

Number of pages | 6 |

Journal | Journal of Chemical Physics |

Volume | 57 |

Issue number | 8 |

Publication status | Published - 1972 |

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### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics

### Cite this

*Journal of Chemical Physics*,

*57*(8), 3156-3161.

**On moment conserving decoupling techniques for electron propagators.** / Babu, S. V.; Ratner, Mark A.

Research output: Contribution to journal › Article

*Journal of Chemical Physics*, vol. 57, no. 8, pp. 3156-3161.

}

TY - JOUR

T1 - On moment conserving decoupling techniques for electron propagators

AU - Babu, S. V.

AU - Ratner, Mark A

PY - 1972

Y1 - 1972

N2 - Moment-conserving decoupling procedures for the one-electron Green's function (electron propagator) are investigated. By analysis of one particular system (Hubbard model) it becomes clear that the momentconserving techniques so far proposed for interacting systems are all special cases of [l, 0], [2, 1], or [3, 2] Padè approximants differing only in which terms they omit, how they define self-consistency, and which operator algebra they utilize. The number of formally conserved moments appears not to be a particularly useful criterion of the accuracy of a decoupling procedure, since a two-moment scheme ( HartreeFock) may be numerically closer to the exact answer than some three-moment procedures. Use of the complete Fade approximant, as suggested by Lukman and Goscinski for the particle-hole propagator, appears to be the most consistent method.

AB - Moment-conserving decoupling procedures for the one-electron Green's function (electron propagator) are investigated. By analysis of one particular system (Hubbard model) it becomes clear that the momentconserving techniques so far proposed for interacting systems are all special cases of [l, 0], [2, 1], or [3, 2] Padè approximants differing only in which terms they omit, how they define self-consistency, and which operator algebra they utilize. The number of formally conserved moments appears not to be a particularly useful criterion of the accuracy of a decoupling procedure, since a two-moment scheme ( HartreeFock) may be numerically closer to the exact answer than some three-moment procedures. Use of the complete Fade approximant, as suggested by Lukman and Goscinski for the particle-hole propagator, appears to be the most consistent method.

UR - http://www.scopus.com/inward/record.url?scp=36849112041&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=36849112041&partnerID=8YFLogxK

M3 - Article

VL - 57

SP - 3156

EP - 3161

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 8

ER -