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arXiv 1204.4728cond-mat.str-elquant-ph
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关联拓扑绝缘体中π磁通的拓扑不变量和量子自旋模型

Topological Invariant and Quantum Spin Models from Magnetic π Fluxes in Correlated Topological Insulators

F. F. Assaad, M. Bercx, M. Hohenadler

摘要:

一个π磁通绝热插入量子自旋霍尔绝缘体,产生局域自旋和电荷磁通态。以Kane-Mele-哈伯德模型为例,证明了π通量可以用于精确的量子蒙特卡罗模拟来识别相关的Z_2拓扑绝缘体.在存在排斥相互作用的情况下,π通量产生具有居里定律签名的磁化率的Kramers双重自旋态。电子关联还提供了具有可调能量的磁激子的玻色子模式,其充当交换粒子并介导自旋子之间的可调范围和强度的动态相互作用。因此,π通量可以用来建立相互作用的自旋模型。这个想法适用于三自旋环和一维自旋链。具有π通量的关联拓扑绝缘体由于可以自由地产生几乎任意的自旋晶格,代表了一种新型的量子模拟器,可能对数值模拟和实验有用。

英文摘要:

The adiabatic insertion of a πflux into a quantum spin Hall insulator gives rise to localized spin and charge fluxon states. We demonstrate that πfluxes can be used in exact quantum Monte Carlo simulations to identify a correlated Z_2 topological insulator using the example of the Kane-Mele-Hubbard model. In the presence of repulsive interactions, a πflux gives rise to a Kramers doublet of spinon states with a Curie law signature in the magnetic susceptibility. Electronic correlations also provide a bosonic mode of magnetic excitons with tunable energy that act as exchange particles and mediate a dynamical interaction of adjustable range and strength between spinons. πfluxes can therefore be used to build models of interacting spins. This idea is applied to a three-spin ring and to one-dimensional spin chains. Due to the freedom to create almost arbitrary spin lattices, correlated topological insulators with πfluxes represent a novel kind of quantum simulator potentially useful for numerical simulations and experiments.

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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