Z 2 -slave-spin theory for strongly correlated fermions
Z 2 -slave-spin theory for strongly correlated fermions
复制标题
DOI：
10.1103/physrevb.81.155118
复制
发表时间：
2009-12
影响因子：
3.7
通讯作者：
A. Rüegg;A. Rüegg;S. Huber;S. Huber;M. Sigrist
中科院分区：
文献类型：
--
作者：
A. Rüegg;A. Rüegg;S. Huber;S. Huber;M. Sigrist
我们回顾了一种基于辅助赝旋变量的类Hubbard模型的表示。这些伪自旋指的是原始模型中模2的局域电荷，并显示了局域的${\mathsf{Z}}_{2}$规范自由度。我们在各种不同的背景下讨论了与相互作用驱动的金属-绝缘体半填充相变问题相关的平均场理论，包括费米表面形变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带是由横场中的Ising模型的激发得到的，并且该模型的量子临界点与几乎定域费米液态场的Brinkman-Rice临界点相一致。利用团簇平均场近似和辅助量子伊辛模型的Schwinger玻色子理论考虑了非局域关联。
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 ${\mathsf{Z}}_{2}$ 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. Nonlocal correlations are included using a cluster mean-field approximation and the Schwinger boson theory for the auxiliary quantum Ising model.