Delayed sudden birth of entanglement
Delayed sudden birth of entanglement
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DOI：
10.1103/physreva.77.054301
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发表时间：
2008-05-01
影响因子：
2.9
通讯作者：
Tanas, Ryszard
中科院分区：
文献类型：
--
作者：
Ficek, Zbigniew;Tanas, Ryszard
研究了自发辐射耗散过程产生纠缠的时间延迟概念。发现了产生纠缠的阈值效应，其中最初未纠缠的量子比特可以在有限时间后纠缠，尽管量子比特之间的相干始终存在。这种纠缠的延迟产生，我们称之为纠缠的突然诞生，与目前广泛讨论的纠缠突然死亡相反，是系统单光子纠缠态的瞬时动力学的特征。我们确定了产生纠缠的阈值时间，并发现它与反对称态仍然是唯一被填充的激发态的时间有关。结果表明，阈值时间可以由量子比特之间的距离和初始激发相对于原子间轴的方向来控制。这一效应为纠缠的研究提供了一种替代方案，并为按需创建两个量子比特之间的纠缠提供了一个有趣的资源。
The concept of time delayed creation of entanglement by the dissipative process of spontaneous emission is investigated. A threshold effect for the creation of entanglement is found where the initially unentangled qubits can be entangled after a finite time despite the fact that the coherence between the qubits exists for all times. This delayed creation of entanglement, which we call sudden birth of entanglement, is opposite to the currently extensively discussed sudden death of entanglement and is characteristic for transient dynamics of one-photon entangled states of the system. We determine the threshold time for the creation of entanglement and find it is related to time at which the antisymmetric state remains the only excited state being populated. It is shown that the threshold time can be controlled by the distance between the qubits and the direction of initial excitation relative to the interatomic axis. This effect suggests an alternative for the study of entanglement and provides an interesting resource for creation on demand of entanglement between two qubits.