On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square Lattice
The dynamical mean-field approximation (DMFA) becomes exact in the limit of infinite dimensions, and allows results to be obtained in a nonperturbative regime without the limitations normally found with exact diagonalization (ED) and quantum Monte Carlo (QMC) methods. In this paper, we investigate t...
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| Format: | Article |
| Language: | English |
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Wiley
2010-01-01
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| Series: | Advances in Condensed Matter Physics |
| Online Access: | http://dx.doi.org/10.1155/2010/487381 |
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| author | A. N. Ribeiro C. A. Macedo |
| author_facet | A. N. Ribeiro C. A. Macedo |
| author_sort | A. N. Ribeiro |
| collection | DOAJ |
| description | The dynamical mean-field approximation (DMFA) becomes exact in the limit of infinite dimensions, and allows results to be obtained in a nonperturbative regime without the limitations normally found with exact diagonalization (ED) and quantum Monte Carlo (QMC) methods. In this paper, we investigate the applicability of the method to lattices with small coordination number in special situations. Specifically we use this approximation to study the two-dimensional (2D) Hubbard model on a square lattice far from half filling. In this situation, we calculate the specific heat and find that when the filling decreases, that is, antiferromagnetic correlations become less important, the agreement between DMFA and QMC results increases. Our results show that the DMFA can be a valuable technique for studying the thermodynamic properties of the Hubbard model also on a square lattice, but within a parameter range in which the antiferromagnetic correlations are not important. |
| format | Article |
| id | doaj-art-ce9d26be177e46c3a055cb23389884f7 |
| institution | Kabale University |
| issn | 1687-8108 1687-8124 |
| language | English |
| publishDate | 2010-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Condensed Matter Physics |
| spelling | doaj-art-ce9d26be177e46c3a055cb23389884f72025-02-03T01:30:17ZengWileyAdvances in Condensed Matter Physics1687-81081687-81242010-01-01201010.1155/2010/487381487381On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square LatticeA. N. Ribeiro0C. A. Macedo1Departamento de Fisica, Universidade Federal de Sergipe, 49100-000 Sao Cristovao-SE, BrazilDepartamento de Fisica, Universidade Federal de Sergipe, 49100-000 Sao Cristovao-SE, BrazilThe dynamical mean-field approximation (DMFA) becomes exact in the limit of infinite dimensions, and allows results to be obtained in a nonperturbative regime without the limitations normally found with exact diagonalization (ED) and quantum Monte Carlo (QMC) methods. In this paper, we investigate the applicability of the method to lattices with small coordination number in special situations. Specifically we use this approximation to study the two-dimensional (2D) Hubbard model on a square lattice far from half filling. In this situation, we calculate the specific heat and find that when the filling decreases, that is, antiferromagnetic correlations become less important, the agreement between DMFA and QMC results increases. Our results show that the DMFA can be a valuable technique for studying the thermodynamic properties of the Hubbard model also on a square lattice, but within a parameter range in which the antiferromagnetic correlations are not important.http://dx.doi.org/10.1155/2010/487381 |
| spellingShingle | A. N. Ribeiro C. A. Macedo On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square Lattice Advances in Condensed Matter Physics |
| title | On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square Lattice |
| title_full | On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square Lattice |
| title_fullStr | On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square Lattice |
| title_full_unstemmed | On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square Lattice |
| title_short | On the Validity of the Dynamical Mean-Field Approximation for Studying the Two-Dimensional Hubbard Model on a Square Lattice |
| title_sort | on the validity of the dynamical mean field approximation for studying the two dimensional hubbard model on a square lattice |
| url | http://dx.doi.org/10.1155/2010/487381 |
| work_keys_str_mv | AT anribeiro onthevalidityofthedynamicalmeanfieldapproximationforstudyingthetwodimensionalhubbardmodelonasquarelattice AT camacedo onthevalidityofthedynamicalmeanfieldapproximationforstudyingthetwodimensionalhubbardmodelonasquarelattice |