物理学报2017，Vol.66Issue(23)：46-55,10.DOI:10.7498/aps.66.230304
具有三角自旋环的伊辛-海森伯链的热纠缠
Thermal entanglement of Ising-Heisenberg chain with triangular plaquettes
摘要
Abstract
Quantum entanglement as an important resource in quantum computation and quantum information has attracted much attention in recent decades. The effect of temperature should be viewed as an external control in the preparation of entangled state, and the thermal entanglement of the Heisenberg spin model has been discussed intensively. Due to the quantum fluctuation and thermal effect, there have been found some interesting physical phenomena in the geometrically frustrated spin system at zero or a certain temperature. Meanwhile, the lattice spin system with triangular plaquettes is regarded as a general structure of magnetic material. In this paper, we theoretically analyze the thermal entanglement of Ising-Heisenberg chain with triangular plaquettes. The transfer matrix method is used to calculate numerically the thermal entanglement in the infinite Ising-Heisenberg chain. We consider three kinds of Heisenberg spin interaction models (i.e., XXX-Heisenberg model, XXZ-Heisenberg model and XY Z-Heisenberg model), and discuss the effects of magnetic field and temperature on the three models, respectively. The results show that temperature and magnetic field have important effects on the three models. Meanwhile, it is found that the XXX-Heisenberg model is more sensitive than the anisotropy model (i.e., XXZ-Heisenberg model or XY Z-Heisenberg model) when temperature rises. A certain magnetic field would promote the generation of the quantum entangled states in all the three cases when the thermal fluctuation suppresses the quantum effects of the systems. In addition, it is found that the entanglement of XY Z-Heisenberg model is more robust than the others at a higher temperature, especially when the anisotropy along the z axis is greater than that along the y axis. We also plot the variations of the critical temperature with magnetic field in the three models. From the critical temperature-magnetic field phase diagrams, we can obtain the range of parameters in which the pairwise entanglement of the system exists. We also find that the entanglement revival behaviors may occur in a specific range of the parameters. Therefore, the properties of the thermal entanglement of Ising-Heisenberg chain with triangular plaquettes can be controlled and enhanced by choosing and using suitable parameters of magnetic field and temperature.关键词
热纠缠/配对纠缠度/伊辛-海森伯链/转移矩阵方法Key words
thermal entanglement/pairwise concurrence/Ising-Heisenberg chain/transfer matrix ap-proach引用本文复制引用
郑一丹,毛竹,周斌..具有三角自旋环的伊辛-海森伯链的热纠缠[J].物理学报,2017,66(23):46-55,10.基金项目
国家自然科学基金 (批准号: 11274102)、教育部新世纪优秀人才支持计划 (批准号: NCET-11-0960) 和高等学校博士学科点专项科研基金 (批准号: 20134208110001) 资助的课题. Project supported by the National Natural Science Foundation of China (Grant No. 11274102), the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-11-0960), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20134208110001). （批准号: 11274102）
