Heisenberg XX自旋环中的纠缠开关

研究了在均匀磁场中的三格点Heisenberg XX自旋环,通过控制一个格点的耦合参数,来调控另外两个格点之间的纠缠.理论上发现当控制格点的耦合参数比未控制格点的耦合参数小时,未控制格点间的纠缠随磁场变化会出现一个纠缠值为1的平台.在较低温度下,平台的宽度与未控制格点间的耦合参数值相等,是一个很好的纠缠开关.同时,分析了存在两个控制格点的情况,也可以得到纠缠值为1的开关,并发现自旋相互作用具有线性关系.

Entanglement Switch in Heisenberg XX Spin Rings

This paper is devoted to analyse the three-qubit Heisenberg XX rings in a uniform magnetic field,and by controlling of the coupling of a site we can change the entanglement between other two sites.We find that thermal entanglement exhibits a platform-like behaviour and entangled value is equal to 1 when coupling of the site which was controlled is small than that was not controlled,the width of the platform-like region could be controlled by changing the coupling between was not sites,This novel property may be used as a quantum entanglement switch.At the same time,we analyse the situation that two sites were controlled,the entanglement maximal switch still can be realized.Moreover,we find that there are linear relation in the spin-spin interactions.