基于一个三量子比特海森堡链的热纠缠研究  

Thermal Entanglement of a Three Qubits Heisenberg Chain

作　　者：刘玉强 杨国晖[2] LIU Yu-qiang;YANG Guo-hui(School of Physics,Dalian University of Technology,Dalian 116023,Liaoning,China;School of Physics and Information Engineering,Shanxi Normal University,Linfen 041004,Shanxi,China)

机构地区：[1]大连理工大学物理学院,辽宁大连116023 [2]山西师范大学物理与信息工程学院,山西临汾041000

出　　处：《山西师范大学学报（自然科学版）》2018年第3期51-55,共5页Journal of Shanxi Normal University(Natural Science Edition)

摘　　要：利用Concurrence判据研究了一个三比特海森堡链的热纠缠性质.研究发现,在有限温度下,纠缠瞬间产生的现象存在于近邻纠缠C12和次近邻纠缠C13的演化中,不同的是,C12的演化中始终存在纠缠瞬间产生的现象,而C13的演化只有当温度高于临界值Tc时,这种现象才能发生.其次,温度为定值时,C12的存在范围随磁场的增大而减小,而C13的存在范围随磁场的的增大保持不变.在温度趋于0的极限情况下,C12为零,而C13达到峰值,即次近邻比特间可获得最大纠缠.此外,磁场的增大拓宽了C12和C13存在的温度的取值范围,即通过调节磁场可在较高温度获得比特间纠缠.Using the Concurrence criterion,the thermal entanglement of a three-qubit Heisenberg chain is investigated. It is shown that the sudden birth phenomenon（ SBP） occurred in the behavior of C12 and C13. With the finite temperature,there is one apparent difference is that the sudden birth phenomenon always exits in the behavior of C12,while this phenomenon is occurred in the behavior of C13 until at a critical temperature. Furthermore,with fixed temperature,the existence region of C12 is increased initially and then decreased with increasing T,while C13 remains constant. In limit case of T→ 0,the C12 coefficient is zero,however,the C13 coefficient is reached the peak,that is to say,the maximum can be obtained between the next nearest neighbor qubits. In addition,increasing magnetic field can broaden the existence scope of temperature of C12 and C13,that is to say,the entanglement between qubits can be obtained at higher temperature by adjusting magnetic field.

关 键 词：三量子比特体系 海森堡模型 热纠缠 CONCURRENCE 

分 类 号：O469[理学—凝聚态物理]