Institute for Quantum Computing and Department of Physics & Astronomy, University of Waterloo, Waterloo, Canada, N2L 3G1.
Phys Rev Lett. 2009 Dec 11;103(24):240504. doi: 10.1103/PhysRevLett.103.240504.
We introduce and implement a technique to extend the quantum computational power of cluster states by replacing some projective measurements with generalized quantum measurements (POVMs). As an experimental demonstration we fully realize an arbitrary three-qubit cluster computation by implementing a tunable linear-optical POVM, as well as fast active feedforward, on a two-qubit photonic cluster state. Over 206 different computations, the average output fidelity is 0.9832+/-0.0002; furthermore the error contribution from our POVM device and feedforward is only of O(10(-3)), less than some recent thresholds for fault-tolerant cluster computing.
我们介绍并实现了一种通过用广义量子测量（POVM）替代部分投影测量来扩展簇态的量子计算能力的技术。作为一个实验演示，我们通过在一个两量子比特光子簇态上实现一个可调谐的线性光学 POVM 以及快速主动前馈，完全实现了任意的三量子比特簇计算。在超过 206 次不同的计算中，平均输出保真度为 0.9832+/-0.0002；此外，来自我们的 POVM 设备和前馈的误差贡献仅为 O(10(-3))，低于一些最近容错簇计算的阈值。
