He Mingjian, Malaney Robert
School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
Sci Rep. 2022 Oct 13;12(1):17169. doi: 10.1038/s41598-022-21283-4.
Hybrid entanglement between discrete-variable (DV) and continuous-variable (CV) quantum systems is an essential resource for heterogeneous quantum networks. Our previous work showed that in lossy channels the teleportation of DV qubits, via CV-entangled states, can be significantly improved by a new protocol defined by a modified Bell state measurement at the sender. This work explores whether a new, similarly modified, CV-based teleportation protocol can lead to improvement in the transfer of hybrid entangled states. To set the scene, we first determine the performance of such a modified protocol in teleporting CV-only qubits, showing that significant improvement over traditional CV-based teleportation is obtained. We then explore similar modifications in the teleportation of a specific hybrid entangled state showing that significant improvement over traditional CV-based teleportation is again found. For a given channel loss, we find teleporting the DV qubit of the hybrid entangled state can always achieve higher fidelity than teleporting the CV qubit. We then explore the use of various non-Gaussian operations in our modified teleportation protocol, finding that, at a cost of lower success probability, quantum scissors provides the most improvement in the loss tolerance. Our new results emphasize that in lossy conditions, the quantum measurements undertaken at the sender can have a surprising and dramatic impact on CV-based teleportation.
离散变量（DV）与连续变量（CV）量子系统之间的混合纠缠是异构量子网络的重要资源。我们之前的工作表明，在有损信道中，通过发送方的一种经修改的贝尔态测量所定义的新协议，利用CV纠缠态进行DV量子比特的隐形传态可以得到显著改善。这项工作探讨了一种类似地经修改的基于CV的新隐形传态协议是否能改善混合纠缠态的传输。为了做好铺垫，我们首先确定这种修改后的协议在仅对CV量子比特进行隐形传态时的性能，结果表明与传统的基于CV的隐形传态相比有显著改进。然后我们在特定混合纠缠态的隐形传态中探索类似的修改，结果再次表明与传统的基于CV的隐形传态相比有显著改进。对于给定的信道损耗，我们发现对混合纠缠态的DV量子比特进行隐形传态总是能比传送CV量子比特实现更高的保真度。然后我们在修改后的隐形传态协议中探索各种非高斯操作的使用，发现以较低的成功概率为代价，量子剪刀在损耗容限方面提供了最大的改进。我们的新结果强调，在有损条件下，发送方进行的量子测量会对基于CV的隐形传态产生惊人且显著影响。
