Quantum phase transitions in three-leg spin tubes
Quantum phase transitions in three-leg spin tubes
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DOI：
10.1103/physrevb.82.075108
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发表时间：
2010-05
影响因子：
3.7
通讯作者：
D. Charrier;S. Capponi;M. Oshikawa;P. Pujol
中科院分区：
文献类型：
--
作者：
D. Charrier;S. Capponi;M. Oshikawa;P. Pujol
我们利用密度矩阵重整化群方法、强耦合方法和非线性sigma模型研究了三腿量子自旋管的性质。对于整数$S$，该模型被证明表现出一个特别丰富的相图组成的合奏$2S $相变。它们可以通过一个非定域弦序参量的行为来精确地识别，这个非定域弦序参量与哈密顿量中的一个隐藏对称性的破缺有关。这些过渡的性质进一步阐明了不同的方法。我们进行了详细的DMRG分析在特定的情况下$S=1$。数值计算结果证实了存在两个隐藏对称性破缺的Halcohol相，它们被一个平凡的单重态分开。对差距和冯·诺依曼熵的研究表明，在量子自旋管的相图中，一级相变发生在将无间隙线和一级相变线分开的三临界点附近。
We investigate the properties of a three-leg quantum spin tube using several techniques such as the density-matrix renormalization-group (DMRG) method, strong-coupling approaches and the nonlinear sigma model. For integer $S$, the model proves to exhibit a particularly rich phase diagram consisting of an ensemble of $2S$ phase transitions. They can be accurately identified by the behavior of a nonlocal string order parameter associated to the breaking of a hidden symmetry in the Hamiltonian. The nature of these transitions is further elucidated within the different approaches. We carry a detailed DMRG analysis in the specific cases $S=1$. The numerical data confirm the existence of two Haldane phases with broken hidden symmetry separated by a trivial singlet state. The study of the gap and of the von Neumann entropy suggest a first-order phase transition but at the close proximity of a tricritical point separating a gapless and a first-order transition line in the phase diagram of the quantum spin tube.