SAMOP 2023 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 28: Quantum Technologies: Trapped Ions (joint session Q/QI)
Q 28.7: Talk
Wednesday, March 8, 2023, 12:30–12:45, F342
Mixed qubit types in registers of trapped barium ions — •Fabian Pokorny, Andres Vazquez-Brennan, Jamie Leppard, Ana Sotirova, and Chris Ballance — Department of Physics, University of Oxford, United Kingdom
Registers of mixed qubit types are a promising approach for scaling trapped-ion quantum computers. The insensitivity of one qubit type to the others’ light fields eliminates scattering errors and enables advanced qubit control schemes.
Barium-ion qubits are uniquely suited for realising this approach. Their long-lived metastable states allow for the implementation of different qubit types using just one atomic species, which, combined with atomic transitions in the visible range, significantly reduces experimental complexity [1]. In our experiment we use 137Ba+, whose nuclear spin of 3/2 provides magnetic-field insensitive ‘clock’ qubits in both the stable ground-state manifold and the long-lived metastable 5D5/2 manifold. The ground and metastable level qubits are connected via a pair of ‘clock’ transitions, and both qubit types can be driven using a two-photon Raman process with 532 nm light and low scattering error.
We show an all-fiber Raman system capable of single-ion addressing in a large qubit register and further demonstrate simultaneous manipulation of ground-state and metastable-state qubits. These are prerequisites for working with long registers of mixed qubit types and for realising partial projective measurements and mid-circuit measurements.
[1] D. Allcock et al., Applied Physics Letters, vol. 119, 2021.