Entanglement in SU(2)-invariant quantum spin systems
Entanglement in SU(2)-invariant quantum spin systems
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DOI：
10.1103/physreva.68.012309
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发表时间：
2002-12
影响因子：
2.9
通讯作者：
J. Schliemann
中科院分区：
文献类型：
--
作者：
J. Schliemann
利用Peres-Horodecki判据分析了两个自旋S1， S2的SU(2)-不变密度矩阵的纠缠态。这种密度矩阵产生于各向同性自旋系统的热平衡态。这种状态的偏转置与原矩阵具有相同的多重结构和简并度，且最大多重度特征值非负。对于各向同性海森堡自旋模型，S1=S, S2=1/2的情况可以完全求解，并进行了详细的讨论。而且，在这种情况下，Peres-Horodecki准则被证明是不可分性的充分条件。我们还刻画了长度为1的两个自旋的SU(2)不变态。
We analyze the entanglement of SU(2)-invariant density matrices of two spins S1, S2 using the Peres-Horodecki criterion. Such density matrices arise from thermal equilibrium states of isotropic-spin systems. The partial transpose of such a state has the same multiplet structure and degeneracies as the original matrix with the eigenvalue of largest multiplicity being non-negative. The case S1=S, S2=1/2 can be solved completely and is discussed in detail with respect to isotropic Heisenberg spin models. Moreover, in this case the Peres-Horodecki criterion turns out to be a sufficient condition for nonseparability. We also characterize SU(2)-invariant states of two spins of length 1.