基于弱测量和量子反转测量操作下XX自旋链中的量子态传递

The Quantum State Transfer in 1D XX Spin Chain under Weak Measurements and Quantum Measurement Reversals

研究了弱测量和量子测量反转操作对一维XX自旋链中输入态1/2(1/2)(|01〉+|10〉)传递的影响。研究表明,通过合理地控制两种操作强度,弱测量操作与量子测量反转操作结合方案可以概率性地抑制自旋链的退相干作用,从而提高纠缠转移量及保真度。进一步的研究表明,量子测量反转操作促进输入态的传递,而弱测量操作阻碍输入态的传递并且操作强度越大阻碍作用越明显,这一点与前人研究中弱测量操作表现出来的积极作用截然相反。另外,在热力学极限下,量子测量反转操作仍然可以促进量子态的传递,并且对不同的操作强度相应的纠缠转移量及保真度最大值随格点m的分布曲线相互独立。

The effects of weak measurements and quantum measurement reversals on the the transmission of input state1/2（1/2）（｜01〉＋｜10〉）in 1DXX spin chain were investigated.The results showed that,by suitablycontrolling the operations’ strengths,the scheme of the combination of weak measurements and quantum measurement reversals can suppress the decoherence of a spin chain by certain probability,so that the degree of entanglement transfer,and the fidelity can be enhanced.The further studies indicated that quantum measurement reversals can improve the input state transfer,while the weak measurements do hinder the input state transfer and the larger of the weak measurements’ strength is,the stronger of the hinder is.The effect of weak measurements on the quantum state transfer was opposite to the previous researches.In addition,in the thermodynamic limit,the input state transfer can still be improved by quantum reversal measurements and for different operation’s strength the corresponding distribution curves of maximum entanglement transfer and fidelity with lattice m develop size-independent.