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arXiv 2011.08749quant-ph
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量子信道经典容量的实验下限

Experimental Lower Bounds to the Classical Capacity of Quantum Channels

Mario A. Ciampini, Álvaro Cuevas, Paolo Mataloni, Chiara Macchiavello, Massimiliano F. Sacchi

摘要:

我们展示了一个实验过程来证明噪声量子比特信道的经典容量。该方法利用固定的二分纠缠态,其中系统量子比特被发送到信道输入,并且在信道输出和辅助量子比特处执行局部测量$σ_{x}\otimesσ_{x}$、$σ_{y}\otimesσ_{y}$和$σ_{z}\otimesσ_{z}$的集合,因此不求助于全量子过程层析成像。然后通过重建条件概率集、噪声反卷积和相关互信息的经典优化来实现对经典容量的见证。利用一个双光子偏振纠缠态在泡利通道和振幅阻尼通道中对该方法提供经典容量下界的性能进行了测试。测量的信道的下界与模拟数据高度一致,这既考虑了输入态的实验纠缠保真度$F=0.979\pm 0.011$和系统的实验缺陷。

英文摘要:

We show an experimental procedure to certify the classical capacity for noisy qubit channels. The method makes use of a fixed bipartite entangled state, where the system qubit is sent to the channel input and the set of local measurements $σ_{x}\otimesσ_{x}$, $σ_{y}\otimesσ_{y}$ and $σ_{z}\otimesσ_{z}$ is performed at the channel output and the ancilla qubit, thus without resorting to full quantum process tomography. The witness to the classical capacity is then achieved by reconstructing sets of conditional probabilities, noise deconvolution, and classical optimization of the pertaining mutual information. The performance of the method to provide lower bounds to the classical capacity is tested by a two-photon polarization entangled state in Pauli channels and amplitude damping channels. The measured lower bounds to the channels are in high agreement with the simulated data, which take into account both the experimental entanglement fidelity $F=0.979\pm 0.011$ of the input state and the systematic experimental imperfections.

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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