Distributed quantum sensing enhanced by continuous-variable error correction
Distributed quantum sensing enhanced by continuous-variable error correction
复制标题
DOI：
10.1088/1367-2630/ab7257
复制
发表时间：
2019-10
影响因子：
3.3
通讯作者：
Quntao Zhuang;J. Preskill;Liang Jiang
中科院分区：
文献类型：
--
作者：
Quntao Zhuang;J. Preskill;Liang Jiang
分布式感测协议使用本地感测节点的网络来估计网络的全局特征，诸如本地可检测参数的加权平均。在无噪声的情况下，节点共享的连续变量(CV)多体纠缠可以提高参数估计的精度，相对于没有共享纠缠的网络所能达到的精度；对于纠缠协议，均方根估计误差与感知节点数量M接近1/M，即所谓的海森伯格尺度，而对于没有纠缠的协议，误差大约是1/M。然而，在存在损耗和其他噪声源的情况下，尽管多体纠缠在传感位移和相位方面仍然具有一些优势，但M的精度标度并不是很有利。在本文中，我们证明了使用CV纠错码可以增强传感协议对缺陷的健壮性，并使Heisenberg伸缩性恢复到M的中值。此外，针对以前的分布式传感协议只能测量单个正交值的情况，我们构造了一种可以同时检测两个正交值的协议。我们的工作证明了CV纠错码在现实传感场景中的价值。
A distributed sensing protocol uses a network of local sensing nodes to estimate a global feature of the network, such as a weighted average of locally detectable parameters. In the noiseless case, continuous-variable (CV) multipartite entanglement shared by the nodes can improve the precision of parameter estimation relative to the precision attainable by a network without shared entanglement; for an entangled protocol, the root mean square estimation error scales like 1/M with the number M of sensing nodes, the so-called Heisenberg scaling, while for protocols without entanglement, the error scales like 1 / M . However, in the presence of loss and other noise sources, although multipartite entanglement still has some advantages for sensing displacements and phases, the scaling of the precision with M is less favorable. In this paper, we show that using CV error correction codes can enhance the robustness of sensing protocols against imperfections and reinstate Heisenberg scaling up to moderate values of M. Furthermore, while previous distributed sensing protocols could measure only a single quadrature, we construct a protocol in which both quadratures can be sensed simultaneously. Our work demonstrates the value of CV error correction codes in realistic sensing scenarios.