Fewer Lasers Achieve Higher Fidelity Logic Gate
Work from within the Hub that has enabled researchers to halve the number of lasers needed to implement a quantum logic gate between two different atomic species, a feat that could help to create a scalable quantum computer, has been highlighted in the American Physical Society's online Physics magazine.
You can read the article on the APS Physics website or delve deeper via the original paper, entitled "Benchmarking a high-fidelity mixed-species entangling gate".
Abstract: We implement a two-qubit logic gate between a 43Ca+ hyperfine qubit and a 88Sr+ 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.
The paper's authors are A. C. Hughes, V. M. Schäfer, K. Thirumalai, D. P. Nadlinger, S. R. Woodrow, D. M. Lucas, and C. J. Ballance.