We present an efficient experimental procedure that certifies nonvanishing quantum capacities for qubit noisy channels. Our method is based on the use of a fixed bipartite entangled state, where the system qubit is sent to the channel input. A particular set of local measurements is performed at the channel output and the ancilla qubit mode, obtaining lower bounds to the quantum capacities for any unknown channel with no need of quantum process tomography. The entangled qubits have a Bell state configuration and are encoded in photon polarization. The lower bounds are found by estimating the Shannon and von Neumann entropies at the output using an optimized basis, whose statistics is obtained by measuring only the three observables ${\sigma }_x\otimes {\sigma }_x$, ${\sigma }_y\otimes {\sigma }_y$, and ${\sigma }_z\otimes {\sigma }_z$.

中文翻译：

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量子通道容量的实验检测

我们提出了一种有效的实验程序，可证明量子比特噪声通道的量子容量不变。我们的方法基于固定的二分纠缠态的使用，其中系统qubit发送到通道输入。在通道输出和辅助量子位模式下执行一组特定的局部测量，无需量子过程层析成像即可获得任何未知通道的量子容量的下限。纠缠的量子比特具有贝尔状态配置，并以光子极化进行编码。下限是通过使用优化的基础估计输出端的Shannon和von Neumann熵来找到的，下限的统计量是通过仅测量三个可观察值而获得的${\sigma }_X\otimes {\sigma }_X$， ${\sigma }_{ÿ}\otimes {\sigma }_{ÿ}$， 和 ${\sigma }_{ž}\otimes {\sigma }_{ž}$。