Block spin density matrix of the inhomogeneous AKLT model
Block spin density matrix of the inhomogeneous AKLT model
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DOI：
10.1007/s11128-008-0080-y
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发表时间：
2008-04
影响因子：
2.5
通讯作者：
Ying Xu;H. Katsura;T. Hirano;V. Korepin
中科院分区：
文献类型：
--
作者：
Ying Xu;H. Katsura;T. Hirano;V. Korepin
研究了一维AKLT自旋链模型的非齐次泛化。每个晶格点的自旋可能不同。在一定条件下，该AKLT模型的基态是唯一的，并由价键固体（VBS）状态描述。我们计算了在这种基态下连续块体自旋的密度矩阵。密度矩阵与块体外的自旋无关。它被对角化并显示为子空间上的投影。证明了对于大块，密度矩阵在子空间中表现为单位阵。冯·诺伊曼熵与雷尼熵重合，等于饱和值。
We study the inhomogeneous generalization of a 1-dimensional AKLT spin chain model. Spins at each lattice site could be different. Under certain conditions, the ground state of this AKLT model is unique and is described by the Valence-Bond-Solid (VBS) state. We calculate the density matrix of a contiguous block of bulk spins in this ground state. The density matrix is independent of spins outside the block. It is diagonalized and shown to be a projector onto a subspace. We prove that for large block the density matrix behaves as the identity in the subspace. The von Neumann entropy coincides with Renyi entropy and is equal to the saturated value.