Ensemble Green's function theory for interacting electrons with degenerate ground states

An ensemble Green's function formalism, based on the von Neumann density matrix approach, to calculate one-electron excitation spectra of a many-electron system with degenerate ground states is proposed. A set of iterative equations for the ensemble Green's function and self-energy is deri...

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Bibliographic Details
Published inarXiv.org
Main Authors Linnér, Erik, Aryasetiawan, Ferdi
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 21.12.2019
Subjects
Approximation
Excitation spectra
Green's functions
Ground state
Mathematical analysis
Physics - Strongly Correlated Electrons
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Summary:An ensemble Green's function formalism, based on the von Neumann density matrix approach, to calculate one-electron excitation spectra of a many-electron system with degenerate ground states is proposed. A set of iterative equations for the ensemble Green's function and self-energy is derived and a simplest approximation corresponding to an ensemble \(GW\) approximation is naturally obtained. The derivation is based on the Schwinger functional derivative technique and does not assume any adiabatic connection between a noninteracting and an interacting ground state.
ISSN:2331-8422
DOI:10.48550/arxiv.1907.07942