標題: Mean field theory of short-range order in strongly correlated low dimensional electronic systems
作者: Rosenstein, Baruch
Li, Dingping
Ma, Tianxing
Kao, H. C.
電子物理學系
Department of Electrophysics
公開日期: 18-Sep-2019
摘要: Mean field approach, although a generally reliable tool that captures major short-range correlations, often fails in symmetric low dimensional strongly correlated electronic systems like those described by the Hubbard model. In these situations a symmetry is almost broken. The problem is linked to the restoration of the symmetry due to strong fluctuations (both quantum and thermal) on all scales. The restoration of symmetry in statistical models of scalar order parameter fields was treated recently successfully on the Gaussian approximation level by symmetrization of the correlators. Here the idea is extended to fermionic systems in which the order parameter is composite. Furthermore, the precision of the correlators can be improved perturbatively. Such a scheme (based on covariant Gaussian approximation) is demonstrated on the one dimensional (1D) and 2D one band Hubbard models by comparison of the correlator with exact diagonalization and MC simulations, respectively.
URI: http://dx.doi.org/10.1103/PhysRevB.100.125140
http://hdl.handle.net/11536/152799
ISSN: 2469-9950
DOI: 10.1103/PhysRevB.100.125140
期刊: PHYSICAL REVIEW B
Volume: 100
Issue: 12
起始頁: 0
結束頁: 0
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