对称N→M远程量子克隆与远程量子态推断
Symmetric $N \to M$ telecloning and remote quantum state inference
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中文总结 AI 辅助
本文提出仅用贝尔态测量（BSM）即可概率实现对称N→M远程量子克隆，其成功概率与接收者数量M无关，还能实现远程量子态推断，且N≥2时无需成对纠缠即可超越经典通信保真度界限。
中文摘要 AI 辅助
在网络的远端节点间传输未知量子态是量子通信的重要特性，但针对N→M远程量子克隆的研究较少，该研究中未知量子态的N个副本被最优地传输给M≥N个接收者。过往工作需要对所有副本和辅助粒子进行全局POVM测量；本文证明，对称N→M远程量子克隆可仅使用序列（或并行）贝尔态测量（BSM）概率性地实现，允许副本空间分离。成功时，每个接收者的约化态保真度达到无克隆定理施加的界限，成功概率与M无关。当BSM“未成功”时，传输保真度仍可能保持较高，测量结果还能提供待远程克隆未知态最接近的泡利本征基信息。从这个意义上说，即使每个接收者自身约化态的保真度未达最优，其仍可根据副本数量的尺度远程推断未知量子态的置信度。本文还分析了超越经典通信保真度界限所需的资源，包括两体不可区分性和各类多体纠缠。令人惊讶的是，在协议的给定迭代中，成对纠缠并非总是提升传输保真度的必要条件，且对于N≥2的情况，成对纠缠绝非超越经典界限的必要条件。
英文摘要
Teleporting unknown quantum states between distant nodes of a network is a significant feature of quantum communication. Few studies, however, have been conducted on $N \to M$ telecloning, in which $N$ copies of an unknown quantum state are optimally teleported to $M \geq N$ receivers. Previous work requires global POVMs on all copies and auxiliaries; here, we show that symmetric $N \to M$ telecloning can be probabilistically performed using only sequential (or parallel) Bell state measurements (BSMs), allowing the copies to be spatially separated. When successful, the fidelity of each receiver's reduced state saturates the bound imposed by the no-cloning theorem, with the probability of success being independent of $M$. In the case of an `unsuccessful' BSM, we show that the teleportation fidelity is likely to remain high, with the measurement outcome also providing information about the closest Pauli eigenbasis to the unknown state being telecloned. In this sense, each receiver can remotely infer the unknown quantum state with a level of confidence that scales with the number of copies, even if the fidelity of their own reduced state is sub-optimal. We additionally analyze the required resources to ensure the classical-communication fidelity bound is surpassed, both in terms of two-qubit inseparability and varying classes of multipartite entanglement. Surprisingly, we uncover that, at a given iteration of the protocol, pairwise entanglement is not always necessary to increase the teleportation fidelity and is never required to beat the classical bound for $N \geq 2$.
发表机构
- Korea Institute for Advanced Study（韩国高等科学技术研究院）
- Queen’s University Belfast（贝尔法斯特女王大学）
- Munster Technological University（芒斯特科技大学）
机构由 AI 辅助整理，请以论文原文为准。
