含能流的横磁场中各向同性XY自旋链在有限温度下的热纠缠研究  

Thermal Entanglement under Finite Temperature of an Isotropic Transverse XY Spin Chain with Energy Current

作　　者：刘丹 张金岩 

机构地区：[1]大连民族大学物理与材料工程学院,辽宁大连116605 [2]鞍山市第八中学,辽宁鞍山114031

出　　处：《大连民族大学学报》2016年第1期56-60,66,共6页Journal of Dalian Minzu University

基　　金：中央高校基本科研业务费专项资金资助项目(DC201502080402);辽宁省教育厅科学研究一般项目(L2013505)

摘　　要：利用拉氏乘子法构建能流算符,使用多体熵积度量方案计算了三比特系统在温度为零时的纠缠和有限温度下的热纠缠性质;根据拉氏乘子的不同区间分析热纠缠随温度、磁场的变化关系,研究了横磁场中各向同性XY自旋链在能量流影响下的能谱。研究发现:当自旋链中没有能量流时,自旋链的极大纠缠为0.46;而当拉氏乘子大于零时,自旋链中出现能量流动,导致体系的热纠缠增加,热纠缠极大值可达到0.92。自旋链中的能量流动会导致体系的热纠缠增加。当体系处于能流相时,横磁场越大,得到的热纠缠就越大。能流的增加,则会导致体系更容易在较低温度获得较大纠缠。The energy current operator was built by Lagrange multiplier method in this paper.The multiple entropy measures were used to calculate both the entanglement under the zero temperature and the thermal entanglement under the finite temperature in the three- qubit system.According to the different interval of the Lagrange multiplier,the changes of thermal entanglement with temperature and magnetic field were analyzed. The energy spectrums were studied under the influence of the energy current in the isotropic transverse XY spin chain. The study found that When the energy current didn＇t flow in the spin chain,the maximum value of entanglement in the spin chain was 0. 46. When the Lagrange multiplier was greater than zero,the energy current began to flow in the spin chain. Those would make the thermal entanglement increase,and the maximum value could be up to 0. 92. The flow of energy would increase the thermal entanglement of the system. When the system was in the energy current phase,the spin chain would have greater thermal entanglement with greater transverse magnetic field. The increase of the energy current would make the system obtain greater entanglement in lower temper-ature.

关 键 词：热纠缠 自旋链 能流 横磁场 

分 类 号：O413.1[理学—理论物理]