Wang Tie-Jun, Wang Chuan
State Key Laboratory of Information Photonics and Optical Communications and School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China.
Sci Rep. 2016 Jan 19;6:19497. doi: 10.1038/srep19497.
Hyperentangled Bell-state analysis (HBSA) is an essential method in high-capacity quantum communication and quantum information processing. Here by replacing the two-qubit controlled-phase gate with the two-qubit SWAP gate, we propose a scheme to distinguish the 16 hyperentangled Bell states completely in both the polarization and the spatial-mode degrees of freedom (DOFs) of two-photon systems. The proposed scheme reduces the use of two-qubit interaction which is fragile and cumbersome, and only one auxiliary particle is required. Meanwhile, it reduces the requirement for initializing the auxiliary particle which works as a temporary quantum memory, and does not have to be actively controlled or measured. Moreover, the state of the auxiliary particle remains unchanged after the HBSA operation, and within the coherence time, the auxiliary particle can be repeatedly used in the next HBSA operation. Therefore, the engineering complexity of our HBSA operation is greatly simplified. Finally, we discuss the feasibility of our scheme with current technologies.
超纠缠贝尔态分析（HBSA）是高容量量子通信和量子信息处理中的一种重要方法。在此，通过用双量子比特交换门替换双量子比特控制相位门，我们提出了一种方案，以在双光子系统的偏振和空间模式自由度（DOF）中完全区分16种超纠缠贝尔态。所提出的方案减少了对脆弱且繁琐的双量子比特相互作用的使用，并且仅需要一个辅助粒子。同时，它降低了对用作临时量子存储器的辅助粒子进行初始化的要求，并且不必对其进行主动控制或测量。此外，在HBSA操作之后，辅助粒子的状态保持不变，并且在相干时间内，辅助粒子可以在下一次HBSA操作中重复使用。因此，我们的HBSA操作的工程复杂性大大简化。最后，我们讨论了我们的方案在当前技术下的可行性。
