We propose a scheme to enhance entanglement from amplitude damping or correlated amplitude damping decoherence. We show that entanglement sudden death time can be prolonged by the initial single-qubit operation combined with local filtering operation. For the amplitude damping channel case, we give the optimal single-qubit operation for arbitrary pure state α|00〉+β|11〉. For the correlated amplitude damping channel case, we find that single-qubit operation on the initial state can not only enhance the final entanglement but also avoid entanglement sudden death. Compared to the previous schemes, the optimal operations and local filtering operations used in our scheme are independent with the decay parameters of the environment.

中文翻译：

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使用单量子比特酉操作和局部滤波操作增强来自振幅阻尼通道的两个量子比特状态的纠缠

我们提出了一种方案来增强来自振幅阻尼或相关振幅阻尼退相干的纠缠。我们表明，初始单量子位操作结合局部滤波操作可以延长纠缠猝死时间。对于幅度阻尼通道情况，我们给出了任意纯态的最优单量子位操作α|00〉+β|11〉. 对于相关振幅阻尼通道的情况，我们发现在初始状态上进行单量子位操作不仅可以增强最终的纠缠，还可以避免纠缠猝死。与之前的方案相比，我们方案中使用的最优操作和局部滤波操作与环境的衰减参数无关。