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arXiv 0709.3250quant-ph
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自隐形传态及其在LOCC估计等任务中的应用

Self-teleportation and its application on LOCC estimation and other tasks

Keiji Matsumoto

摘要:

一种表征量子非局域性的方法是观察LOCC最优协议和全局最优协议在执行某些任务时的品质因数的差异,例如,状态估计、状态判别、克隆和广播。特别是,我们重点讨论了$n$张量未知状态的情况。我们的结论是可分纯态比纠缠纯态更具有非局域性。更具体地说,如果状态是纠缠的,则品质因数的差异是指数小的,并且指数是最大施密特系数的对数。另一方面,在许多情况下,由LOCC估计的可分离状态比由$O(\frac{1}{n})$的全局最优估计差。为了证明纠缠态的能隙是指数小的,我们提出了自隐形传态协议作为LOCC协议的关键组成部分。该协议的目标是利用$| ϕ_θ> ^{\otimes n}$的本征纠缠,在不使用任何额外资源的情况下,通过LOCC传输Alice的那部分量子信息。该协议本身就具有重要意义。

英文摘要:

A way to characterize quantum nonlocality is to see difference in the figure of merit between LOCC optimal protocol and globally optimal protocol in doing certain task, e.g., state estimation, state discrimination, cloning and broadcasting. Especially, we focus on the case where $n$ tensor of unknown states. Our conclusion is that separable pure states are more non-local than entangled pure states. More specifically, the difference in the figure of the merit is exponentially small if the state is entangled, and the exponent is log of the largest Schmidt coefficient. On the other hand, in many cases, estimation of separable states by LOCC is worse than the global optimal estimate by $O(\frac{1}{n})$. To show that the gap is exponentially small for entangled states, we propose self-teleportation protocol as the key component of construct of LOCC protocols. Objective of the protocol is to transfer Alice's part of quantum information by LOCC, using intrinsic entanglement of $| ϕ_θ> ^{\otimes n}$ without using any extra resources. This protocol itself is of interest in its own right.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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