In this paper we consider the generation of a three-qubit GHZ-like thermal state by applying the entanglement swapping scheme of Zukowski {\it et al.} [Ann. N. Y. Acad. Sci. {\bf 755}, 91 (1995)] to three pairs of two-qubit Heisenberg XY chains. The quality of the resulting three-qubit entanglement is studied by analyzing the teleportation fidelity, when it is used as a resource in the teleportation protocol of Karlsson {\it et al.}[Phys. Rev. A {\bf 58}, 4394 (1998)]. We show that even though thermal noise in the original two-qubit states is amplified by the entanglement swapping process, we are still able to achieve nonclassical fidelities for the anisotropic Heisenberg XY chains at finitely higher and higher temperatures by adjusting the strengths of an external magnetic field. This has a positive implication on the solid-state realization of a quantum computer.
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机译：在本文中，我们考虑通过应用Zukowski {\ it等人}的纠缠交换方案来生成类似三比特GHZ的热态。 N. Y. Acad。科学{\ bf 755}，第91页（1995年）]，获得三对两量子位的Heisenberg XY链。当卡尔斯森{\ it et al。} [物理学报。修订版A {\ bf 58}，4394（1998）]。我们表明，即使通过纠缠交换过程放大了原始两个量子位状态下的热噪声，我们仍然能够通过调节外部磁场的强度在有限更高和更高的温度下实现各向异性海森堡XY链的非经典保真度领域。这对量子计算机的固态实现具有积极意义。
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