Hughes A C, Schäfer V M, Thirumalai K, Nadlinger D P, Woodrow S R, Lucas D M, Ballance C J
Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.
Phys Rev Lett. 2020 Aug 21;125(8):080504. doi: 10.1103/PhysRevLett.125.080504.
We implement a two-qubit logic gate between a ^{43}Ca^{+} hyperfine qubit and a ^{88}Sr^{+} Zeeman qubit. For this pair of ion species, the S-P optical transitions are close enough that a single laser of wavelength 402 nm can be used to drive the gate but sufficiently well separated to give good spectral isolation and low photon scattering errors. We characterize the gate by full randomized benchmarking, gate set tomography, and Bell state analysis. The latter method gives a fidelity of 99.8(1)%, comparable to that of the best same-species gates and consistent with known sources of error.
我们在一个(^{43}Ca^{+})超精细量子比特和一个(^{88}Sr^{+})塞曼量子比特之间实现了一个双量子比特逻辑门。对于这一对离子种类，S-P光学跃迁足够接近，以至于波长为402 nm的单束激光可用于驱动该门，但又充分分开以提供良好的光谱隔离和低光子散射误差。我们通过全随机基准测试、门集层析成像和贝尔态分析来表征该门。后一种方法给出的保真度为99.8(1)%，与最佳的同种类门相当，并且与已知的误差源一致。
