掺杂Ising链的量子纠缠特性

Entanglement of the Ising chain with impurity

研究了含杂质三量子位Ising链中正常格点间的纠缠情况,结果表明杂质对正常格点间的纠缠有着重要的影响,它不仅可能使正常格点间消纠缠,在磁场B和温度T的某些特定取值范围内甚至还可以使正常格点间的纠缠大于通常的三量子位(J1=J)或两量子位(J1=0)情形时的对纠缠;对反铁磁体情形在T=0时,若磁场B与Ising链夹角θ=π/2,B→0或θ→0,B<2J,则还可观察到纠缠随J1的变化呈方波形结构。

In this paper, we investigated the influence of impurity on the entanglement between the normal lattice in a three- qubit Ising chain. The results show that the impurity parameter has great effects on the pairwise entanglement, it can make the normal lattice disentangled and sometimes at certain regions of magnetic field B and temperature T, it can even make the concurrence between the normal lattice greater than the general pairwise entanglement of three qubits （J1 = J） or two qubits （J1 =0）. When T=0, for the case of antiferromagnet with the conditions of θ = π/2, B→0 or θ→B 〈 2J, the concurrence shows a square - wave structure with the variation of the impurity parameter J1.