不同方向外磁场下海森堡自旋链的热纠缠  

Thermal entanglements in a Heisenberg spin chain with different external magnetic fields

作　　者：黄利元 HUANG Li-Yuan(School of Information Science and Technology,Xiamen University Tan Kah Kee College,Zhangzhou 363105,China)

机构地区：[1]厦门大学嘉庚学院信息科学与技术学院,漳州363105

出　　处：《原子与分子物理学报》2021年第6期126-130,共5页Journal of Atomic and Molecular Physics

基　　金：厦门大学嘉庚学院校级科研孵化项目(YM2019L02)。

摘　　要：研究了两量子比特的海森堡XXX自旋链分别处于x方向和y方向均匀外磁场时系统的纠缠特性,并用负度N来度量.得到纠缠度N的解析表达式,并在此基础上进行数值计算.仔细讨论了磁场B、温度T和自旋耦合系数J对纠缠度N的影响.结果表明:纠缠度N会随着磁场|B|和温度T的增大而减小,但会随着自旋耦合系数J的增大而增大.另外,增大的J还会使临界磁场|Bc|和临界温度Tth变大.所以,我们可以通过调节B、T和J来控制热纠缠,这对固态系统中通过构建和选择参数调整系统的纠缠度具有一定的作用和意义.研究还发现,加在x方向均匀外磁场和加在y方向均匀外磁场对两量子比特的海森堡XXX自旋链的作用效果是一样的.The thermal entanglement of two-qubit Heisenberg XXX spin chain in x direction and y direction external uniform magnetic field is measured by entanglement N.The effects of the external magnetic field B,the temperature T and the spin coupling coefficient J on entanglement N are discussed in detail.The results show that the entanglement N decreases with the increase of magnetic field|B|and temperature T,but increases with the increasing spin coupling coefficient J.The critical magnetic field|Bc|and threshold temperature Tth also increase when the coupling coefficient J increases.Therefore,the thermal entanglement can be controlled by adjusting the values of B,T and J in various environments,such as strong external magnetic field and high temperature environment.It is also found that the effect of adding uniform external magnetic field in both x direction and y direction is the same for the two-qubit Heisenberg XXX spin chain.

关 键 词：量子光学 热纠缠 负度 海森堡自旋链 外磁场 

分 类 号：O431.2[机械工程—光学工程]