Cao Huan, Morelli Simon, Rozema Lee A, Zhang Chao, Tavakoli Armin, Walther Philip
Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), <a href="https://ror.org/03prydq77">University of Vienna</a>, 1090 Vienna, Austria.
Faculty of Physics, <a href="https://ror.org/00mv8h305">Christian Doppler Laboratory</a> for Photonic Quantum Computer, <a href="https://ror.org/03prydq77">University of Vienna</a>, 1090 Vienna, Austria.
Phys Rev Lett. 2024 Oct 11;133(15):150201. doi: 10.1103/PhysRevLett.133.150201.
Standard procedures for entanglement detection assume that experimenters can exactly implement specific quantum measurements. Here, we depart from such idealizations and investigate, in both theory and experiment, the detection of genuine multipartite entanglement when measurements are subject to small imperfections. For arbitrary qubits number n, we construct multipartite entanglement witnesses where the detrimental influence of the imperfection is independent of n. In a tabletop four-partite photonic experiment, we demonstrate first how a small amount of alignment error can undermine the conclusions drawn from standard entanglement witnesses and then perform the correction analysis. Furthermore, since we consider quantum devices that are trusted but not perfectly controlled, we showcase advantages in terms of noise resilience as compared to device-independent models.
纠缠检测的标准程序假定实验者能够精确地实施特定的量子测量。在此，我们背离此类理想化情况，从理论和实验两方面研究当测量存在微小缺陷时真正多体纠缠的检测。对于任意数量的量子比特n，我们构建了多体纠缠见证者，其中缺陷的有害影响与n无关。在一个桌面四体光子实验中，我们首先展示了少量的对准误差如何破坏从标准纠缠见证者得出的结论，然后进行了校正分析。此外，由于我们考虑的是可信但并非完全可控的量子设备，与与设备无关的模型相比，我们展示了在抗噪声方面的优势。
