摘要:
研究了一维三量子比特海森伯模型中的对纠缠的提高和控制问题,在该系统中引入了Dzymloslfinskii-Moriya(DM)相互作用,通过求解共生来计算两量子比特之间的热纠缠,结果表明:对于XXX模型,引入DM相互作用D,可以诱导铁磁和反铁磁自旋链产生热纠缠,尽管它们产生热纠缠所需的D值大小不同.对于XXZ模型,引入DM相互作用后,可以使原本不存在热纠缠的反铁磁自旋链产生纠缠,而且对于铁磁和反铁磁这两种XXZ自旋链,DM相互作用和各向异性参数△对于热纠缠具有不同的影响,因此选择合适的DM相互作用参数和各向异性参数△,有利于控制和提高热纠缠.此外,通过比较两比特与三比特的XXZ模型,可知无论是铁磁还是反铁磁链,在相同的温度下,三比特模型产生热纠缠需要的DM相互作用更大一些.
Abstract:
In this paper, we study the improvement and manipulation of pairwise thermal entanglement in one-dimentional three-qubit Heisenberg model, where Dzyaloshinskii-Moriya (DM) interaction is considered and concurrence is calculated to research this entanglements property. The results show that for XXX model, DM interaction can induce entanglement in the antiferromagnetic and ferromagnetic spin chains although the required critical values are different for these cases. For XXZ model, by introducing DM interaction D, antiferromagnetic spin chain has entanglement which is absent when D = 0, and in addition, for antiferromagnetic and ferromagnetic cases, DM interaction D and the anisotropy parameter △ have different effects on entanglement. As a result, the entanglement can be controlled and enhanced by choosing appropriate DM interaction and anisotropy parameter. Furthermore, we find that at the same temperature, no matter for antiferromagnetic or ferromagnetic spin chains, the critical DM interaction inducing entanglement should be greater in a three-qubit XXZ model than that in a two-qubit XXZ model.
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