Operating the metastable qubit in Yb⁺

The metastable ("m-type") qubit defined on zero-field hyperfine clock states in the long-lived ²F_7/2⁰ manifold in Yb⁺ gives a promising pathway to low cross-talk, high fidelity multi-qubit operations using the same ion species via the recently proposed "omg blueprint'' for atomic quantum processing [1]. We demonstrate heralded state preparation, single-qubit operations, and state measurement in the m-type qubit of ¹⁷¹Yb⁺, achieving a SPAM infidelity of 4⁺³_-2 X 10^-4. We report progress on a new ion trap apparatus, as well as our progress on utilizing an iodine-referenced Doppler cooling laser [2]. We also report our progress towards extending the toolbox of the m-type qubit by coupling to additional metastable states which can be used to implement two-qubit gates.

[1] Allock et al., Appl. Phys. Lett., 119, 214002 (2021)

[2] Chen et al., Chinese Journal of Physics, https://doi.org/10.1016/j.cjph.2023.12.007 (2023)