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arXiv quant-ph/0307135quant-ph
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自旋链中的纠缠动力学和量子态输运

Entanglement dynamics and quantum state transport in spin chains

V. Subrahmanyam

摘要:

我们研究了一个海森堡XY自旋链的动力学,其中一个未知的状态被编码到一个量子比特或一对纠缠量子比特中,其余的自旋处于极化状态。时间演化涉及到磁振子激发,通过它们,纠缠被传输通过通道。对于大量的量子比特,显式公式的并发,措施的两个量子比特纠缠,和保真度恢复状态的一些距离作为时间的函数计算。与没有纠缠对的初始状态相比,具有纠缠对的量子比特的初始状态表现出更好的保真度,其在更早的时间达到其第一个最大值。特别地,具有处于未知状态的一对量子比特的初始状态(α向上-向上+ β向下-向下)最适合于量子态传输。

英文摘要:

We study the dynamics of a Heisenberg-XY spin chain with an unknown state coded into one qubit or a pair of entangled qubits, with the rest of the spins being in a polarized state. The time evolution involves magnon excitations, and through them the entanglement is transported across the channel. For a large number of qubits, explicit formulae for the concurrences, measures for two-qubit entanglements, and the fidelity for recovering the state some distance away are calculated as functions of time. Initial states with an entangled pair of qubits show better fidelity, which takes its first maximum value at earlier times, compared to initial states with no entangled pair. In particular initial states with a pair of qubits in an unknown state (alpha up-up + beta down-down) are best suited for quantum state transport.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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