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arXiv 1608.02145cond-mat.str-el
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横向磁场中四聚体自旋$1/2$链的零温研究

Zero-temperature study of a tetrameric spin-$1/2$ chain in a transverse magnetic field

J. Vahedi, M. Shabani Arbousara, S. Mahdavifar

摘要:

本文研究了具有空间调制主导反铁磁交换和各向异性铁磁耦合的海森堡自旋- $1/2$反铁磁-铁磁($AF-F$)交替链(四聚体自旋- $1/2$链).数值研究了对称破缺横向磁场对模型的零温效应。结果表明,各向异性对铁磁耦合的影响导致了两个新的带隙相。我们确定了它们的排序为一种条纹反铁磁相。其结果是,四聚链的磁相图显示了五个缺口的量子相位和系统的特征在于由四个临界场标记的量子相变在基态的系统与变化的横向磁场。我们还利用了著名的二体纠缠(称之为并发)和全局纠缠工具来验证量子相变的发生和相应的临界点。

英文摘要:

We consider an alternating Heisenberg spin-$1/2$ antiferromagnetic-ferromagnetic ($AF-F$) chain with the space modulated dominant antiferromagnetic exchange and anisotropic ferromagnetic coupling (tetrameric spin-$1/2$ chain). The zero-temperature effect of a symmetry breaking transverse magnetic field on the model is studied numerically. It is found that the anisotropy effect on the ferromagnetic coupling induces two new gapped phases. We identified their orderings as a kind of the stripe-antiferromagnetic phase. As a result, the magnetic phase diagram of the tetrameric chain shows five gapped quantum phases and the system is characterized by four critical fields which mark quantum phase transitions in the ground state of the system with the changing transverse magnetic field. We have also exploited the well known bipartite entanglement (name as concurrence) and global entanglement tools to verify the occurrence of quantum phase transitions and the corresponding critical points.

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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