Analysis of quantum correlations within the ground state of a three-level Lipkin model
Entity
UAM. Departamento de Física TeóricaPublisher
American Physical SocietyDate
2022-06-27Citation
10.1103/PhysRevA.105.062449
Physical Review A 105.6 (2022): 062449
ISSN
2469-9926 (print); 2469-9934 (online)DOI
10.1103/PhysRevA.105.062449Project
Gobierno de España. PGC2018-094583-B-I00Editor's Version
https://doi.org/10.1103/PhysRevA.105.062449Subjects
Correlation Energy; Field Values; Lipkin Model; Mean Field Methods; Performance; Quantum Correlations; Quantum Discords; Quantum Many-Body Problems; Three-Level; FísicaRights
©2022 American Physical SocietyAbstract
The performance of beyond mean-field methods in solving the quantum many-body problem for fermions is usually characterized by the correlation energy measured with respect to the underlying mean-field value. In this paper we address the issue of characterizing the amount of correlations associated to different approximations from a quantum information perspective. With this goal in mind, we analyze the traditional Hartree-Fock (HF) method with spontaneous symmetry breaking, the HF with symmetry restoration and the generator coordinate method in an exactly solvable fermion model known as the three-level Lipkin model. To characterize correlations including entanglement and beyond we use the quantum discord between different partition orbitals. We find that for physically motivated partitions, the quantum discord of the exact ground state is reasonably well reproduced by the different approximations. However, other partitions create "fake quantum correlations" in order to capture quantum correlations corresponding to partitions for which the Hartree-Fock solution fails. Those are removed and redistributed through a symmetry restoration process
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Google Scholar:Faba, Javier
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Martín, Vicente
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Robledo Martín, Luis Miguel
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