Qubit Recycling in Entanglement Distillation
Qubit Recycling in Entanglement Distillation
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DOI：
10.1109/qce57702.2023.00013
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发表时间：
2023-07
期刊：
影响因子：
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通讯作者：
Stuart Pelletier;Ruozhou Yu;G. Rouskas;Jianqing Liu
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文献类型：
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作者：
Stuart Pelletier;Ruozhou Yu;G. Rouskas;Jianqing Liu
量子纠缠蒸馏是从大量低保真度纠缠中提取少量高保真度纠缠的过程，本质上是用产量（或存活率）换取保真度。在现有的蒸馏方法中，Gisin 的局部过滤协议通常在光子量子系统中采用，用于在偏振基础上蒸馏纠缠光子。然而，Gisin 滤波器的性能也受到保真度和产量之间同样基本权衡的影响。为了应对这一挑战，在这项工作中，我们提出了一种协议，通过设计（和优化）的本地算子来回收处理的光子并提高其保真度。所提出协议的关键参数是通过解决约束优化问题来计算的。通过这样做，我们获得了显着更高的高保真纠缠对产量。我们进一步评估了我们设计的协议在 Gisin 过滤器的两种常见配置（即全过滤器和部分过滤器）下的性能。与现有的蒸馏协议相比，结果表明，我们的设计在相同的保真度下实现了高达 31.2% 的产量增益，同时在投资的硬件和额外的同步信号方面仅产生中等的系统复杂性。
Quantum entanglement distillation is a process to extract a small number of high-fidelity entanglement from a large number of low-fidelity ones, which in essence is to trade yield (or survival rate) for fidelity. Among existing distillation approaches, Gisin's local filtering protocol is commonly adopted in photonic quantum systems for distilling entangled photons in polarization basis. Yet, the performance of Gisin's filter is cursed by the same fundamental trade-off between fidelity and yield. To address this challenge, in this work, we propose a protocol to recycle the disposed photons and improve their fidelity by a designed (and optimized) local operator. The key parameters of the proposed protocol are calculated by solving a constrained optimization problem. In so doing, we achieve significantly higher yield of high-fidelity entanglement pairs. We further evaluate the performance of our designed protocol under two common configurations of Gisin's filter, namely full filter and partial filter. Compared with existing distillation protocols, the results demonstrate that our design achieves as much as 31.2% gain in yield under the same fidelity, while only incurring moderate system complexity in terms of invested hardware and extra signaling for synchronization.