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arXiv 0912.3801cond-mat.str-el
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强关联费米子的Z_2-从自旋理论

Z_2-slave-spin theory for strongly correlated fermions

A. Rüegg, S. D. Huber, M. Sigrist

摘要:

我们回顾了Hubbard模型的表示,是基于辅助赝自旋变量。这些赝自旋指的是原模型中的局域电荷模2,并显示出局域Z_2规范自由度。我们在各种不同的背景下讨论了相关的平均场论,这些背景与半填充时相互作用驱动的金属-绝缘体相变问题有关,包括费米表面变形和超出局域近似的光谱特征。值得注意的是,在平均场水平上,Hubbard带来自于横向场中的伊辛模型的激发,并且该模型的量子临界点与几乎局域化的费米液态的Brinkman-Rice临界性相一致。非局域关联包括使用集团平均场近似和辅助量子伊辛模型的Schwinger玻色子理论。

英文摘要:

We review a representation of Hubbard-like models that is based on auxiliary pseudospin variables. These pseudospins refer to the local charge modulo two in the original model and display a local Z_2 gauge freedom. We discuss the associated mean-field theory in a variety of different contexts which are related to the problem of the interaction-driven metal-insulator transition at half-filling including Fermi surface deformation and spectral features beyond the local approximation. Notably, on the mean-field level, the Hubbard bands are derived from the excitations of an Ising model in a transverse field and the quantum critical point of this model is identified with the Brinkman-Rice criticality of the almost localized Fermi liquid state. Non-local correlations are included using a cluster mean-field approximation and the Schwinger boson theory for the auxiliary quantum Ising model.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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