量子纠缠的普适蒸馏
Universal distillation of quantum entanglement
- The University of Tokyo（东京大学）
- RIKEN Center for Quantum Computing (RQC)（理化学研究所量子计算中心）
- The Chinese University of Hong Kong, Shenzhen（香港中文大学（深圳））
- International Quantum Academy（国际量子学院）
- Nagoya University（名古屋大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出一种不依赖输入态描述的普适LOCC协议，证明即使未知输入态，也能达到最优的可蒸馏纠缠速率，从而将可蒸馏纠缠确立为稳健的操作量。
AI中文摘要：
可蒸馏纠缠——通过局域操作与经典通信（LOCC）从给定的噪声纠缠态中提取贝尔态的最大速率——一直是刻画纠缠态操作价值的核心量。然而，已知这种操作意义仅在关键假设下成立：双方都知晓输入态的描述，并能选择针对该态定制的协议，这并不必然反映自然的操作场景。在此，我们证明即使没有这一假设，可蒸馏纠缠仍是基本的操作量。我们提出一种普适的LOCC协议——其描述不依赖于输入态，因此对任意输入均普适有效——该协议能达到任意未知输入态的可蒸馏纠缠。因此，我们的结果将可蒸馏纠缠提升为具有操作意义的稳健概念，并阐明输入态知识并非实现最优纠缠蒸馏速率所必需。我们的协议基于复合态的状态合并，以及有限块量向可蒸馏纠缠一致收敛的性质。
英文摘要：
Distillable entanglement---the maximum rate of Bell states extractable from the given noisy entangled states via local operations and classical communication (LOCC)---has been a central quantity to characterize the operational value of entangled states. However, this operational meaning had been known to be valid only under a crucial assumption: both parties know the description of the input state and can choose the protocol tailored to it, which does not necessarily reflect the natural operational setting. Here, we show that the distillable entanglement is the fundamental operational quantity even without this assumption. We present a universal LOCC protocol---whose description does not depend on the input state and thus works universally for any input---that achieves the distillable entanglement of an arbitrary unknown input state. Our result therefore lifts the distillable entanglement to a robust notion of an operationally meaningful quantity and clarifies that input-state knowledge is not necessary to achieve the optimal rate of entanglement distillation. Our protocol is based on state merging for compound states, together with the uniform convergence property of the finite-block quantity toward distillable entanglement.
