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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Bibliographic Details
Published in:Advances in condensed matter physics 2010-01, Vol.2010 (2010), p.1-5
Main Authors: Ribeiro, A. N., Macedo, C. A.
Format: Article
Language:English
Subjects:
Antiferromagnetism
Approximation
Computer simulation
Lattices
Mathematical analysis
Mathematical models
Methods
Monte Carlo methods
Numerical analysis
Studies
Temperature effects
Thermodynamic properties
Two dimensional
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Summary: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.
ISSN:1687-8108
1687-8124
DOI:10.1155/2010/487381