论文标题
保存当地嘈杂频道中的纠缠
Preservation of entanglement in local noisy channels
论文作者
论文摘要
纠缠不得不被噪音掩盖，以防止衰减。但是，如果有许多嘈杂的渠道，可以通过使用当地的单一操作来部分防止降解。我们考虑局部噪声对共享量子状态的影响，并评估可以免于恶化的纠缠量。保存的纠缠量不仅取决于通道的强度，还取决于通道的类型，尤其是它始终消失的去极化通道。这项工作的主要动机是通过检查相应渠道的属性来分析保存纠缠的这种依赖的原因。在这种情况下，我们量化并探索了渠道朝着其行动不同状态的偏见。我们假设所有偏见措施必须消失在去极化通道中，然后引入一些偏见措施。我们还考虑渠道的纠缠能力。我们观察到，偏见量化器的共同行为和纠缠能力解释了保存的纠缠的性质。此外，我们在保存的纠缠上找到了一对上限，该范围内被注意到模仿后者的图形性质。
Entanglement subject to noise can not be shielded against decaying. But, in case of many noisy channels, the degradation can be partially prevented by using local unitary operations. We consider the effect of local noise on shared quantum states and evaluate the amount of entanglement that can be preserved from deterioration. The amount of saved entanglement not only depends on the strength of the channel but also on the type of the channel, and in particular, it always vanishes for the depolarizing channel. The main motive of this work is to analyze the reason behind this dependency of saved entanglement by inspecting properties of the corresponding channels. In this context, we quantify and explore the biasnesses of channels towards the different states on which they act. We postulate that all biasness measures must vanish for depolarizing channels, and subsequently introduce a few measures of biasness. We also consider the entanglement capacities of channels. We observe that the joint behaviour of the biasness quantifiers and the entanglement capacity explains the nature of saved entanglement. Furthermore, we find a pair of upper bounds on saved entanglement which are noticed to imitate the graphical nature of the latter.
