具有三体相互作用海森堡自旋链模型的纠缠与几何失协

近年来有研究发现量子失协可以度量非纠缠的量子关联,而且非纠缠的量子关联在量子通信和量子计算中起到很重要的作用.本文研究了磁场,两种三体相互作用,各向异性参数,耦合常数,温度等参数对同时具有两种三体相互作用海森堡XXZ自旋链系统的量子纠缠,几何失协的影响以及与量子相变的关系.研究表明:量子纠缠和几何失协都可以清晰的表征本模型系统的量子相变现象;随着XZX+YZY型三体相互作用的增加量子纠缠和几何失协即使在高温时也可达到最大值;几何失协比量子纠缠更全面地描述了量子关联;XZY-YZX型三体相互作用的增加对量子纠缠有抑制作用;XZY-YZX型三体相互作用在一定区域内的增加对几何失协有抑制作用,在另一区域的增加可使几何失协增大到一个稳定的非零值.增大磁场和自旋耦合常数,减小各向异性参数会使纠缠的临界温度变大;调节自旋耦合常数可更有效的使量子纠缠和几何失协在高温时仍有一个较大的值.同时发现,在磁场0B5和各向异性参数-1J_Z10的区域两种量子关联都可以维持在最大值.

Quantum entanglement and geometric discord in the heisenberg spin chain with three-site interaction

Quantum discord has been widely accepted as a fundamental tool due to its relevance in quantum computing tasks not relying on entanglement. In this paper we investigate the concurrence,geometric discord with reference to quantum phase transtion in the XXZ spin chain with three-site interaction, and analyze the effects of two types of three-site interaction, magnetic field, anisotropy parameter, couping constants J and temperature on C, GD.The result shows that C, GD can characterize the quantum phase transtion phenomena. By increasing , C and GD could achieve the maximum even at high temperature. While the increase of has inhibitive effect on C, and in some regions also has inhibitive effect on GD, however, in some other reigons with the increase of , GD could be enhanced to a steady value. Which implies that GD describes the quantum correlation more comprehensively than C. Additionally, entanglement can be enhanced by decreasing the magnetic field and the anisotropy parameter. The critical temperature is enhanced by increasing of magnetic field and decreasing anisotropy parameter. In particular, the critical temperature increases significantly with the increase of the couping constants J. Moreover, the value of GD differed significantly from 0 even at the higher temperature while J is dreasing. In addition, if the values of the other parameters are fixed, the C, GD reaches maximum value in the region of and .