阻挫自旋梯子的纠缠与量子相变

Entanglement and quantum phase transition in a frustrated spin ladder

对于具有阻挫作用的反铁磁自旋梯子,采用多体格林函数方法并结合Jordan-Wigner变换,计算系统中近邻双格点的纠缠,分析纠缠的奇异性与量子相变之间关系.发现随着外磁场的变化,纠缠出现奇异即发生量子相变,但在量子相变点纠缠不一定出现奇异,这说明纠缠奇异与量子相变并非一一对应,此外纠缠平台与磁化平台一一对应.

The entanglement and quantum phase transition_of the frustrated antiferromagnetic spin ladder had been investigated by means of Green function theory combined with Jordan-Wigner transformation. Herein, the concurrence a measure of the amount of entanglement, had been calculated. It Was founded that the emergence of singularity in concurrence indicated quantum phase transition occured. However, the concurrence might be analytieity at the critical point. That was to say, the coneurrence could not always he used to detect quantum phase transition. It also showed that there was one-to-one correspondence between the magnetization plateau and the entanglement plateau.