从 W 态及类 W 态产生随机二分纠缠
摘要
我们描述了一种协议，用于从共享三方 W 态的各方中，在随机配对的双方之间提炼出最大纠缠的二分态，并出人意料地表明，总提炼率（每个 W 态所提炼的 EPR 对总数，不论由谁共享）可能高于在指定配对双方之间提炼二分纠缠的速率。具体而言，先前已证明 W 态用于指定纠缠的最优提炼率为每 W 态 0.92 个 EPR 对的渐近辅助纠缠，而我们的协议可在随机配对的双方之间渐近地每个 W 态提炼 1 个 EPR 对，我们推测此为最优。因此我们展示了 EPR 提炼的总体渐近速率与最终 EPR 对在各方间分布之间的权衡。我们进一步表明，通过增加协议中的参与方数量，存在这样的态：其对随机各方具有固定的下界可提炼纠缠，而对指定各方的可提炼纠缠可任意小。
引用
@article{arxiv.quant-ph/0607126,
title = {Random bipartite entanglement from W and W-like states},
author = {Ben Fortescue and Hoi-Kwong Lo},
journal= {arXiv preprint arXiv:quant-ph/0607126},
year = {2009}
}
备注
5 pages, 1 figure, RevTeX. v2 - upper bound on random distillation is expressed more generally and corollaries to the bound added. Minor notation changes. v3 - further notation changes (Ernd now designated Et), discussion of finite distillation rounds and single-copy bound on Et added. Theorem added - relative entropy is shown to be an upper bound to Et for all pure states. Discussion of W formation from EPRs (previously shown in others' work) removed. Some addition, removal and reordering of references