Enabling coherent operations in large registers of trapped ions containing multiple qubit types
ORAL
Abstract
Trapped ion devices are amongst the most promising candidates for quantum information processors as they provide naturally identical qubits with long coherence times. One approach to scaling these systems is using multiple qubit types within the same ion species that are insensitive to each others’ light fields. This enables advanced control techniques such as in-sequence cooling and mid-circuit measurements, which are required for many error correction schemes [1]. The long-lived D5/2 metastable level of Ba+ offers an alternative to the ground S1/2 manifold for qubit storage and operations, and does not couple to the S1/2 → P1/2 cycling transition used for Doppler cooling and readout. We present a system that takes advantage of this additional manifold in Ba+ ions to implement the aforementioned control techniques.
Uniquely for barium, qubits implemented in either the ground S1/2 level or metastable D5/2 level can be coherently manipulated via a two-photon Raman process using 532nm light with very low scattering error [2]. Individual qubits are addressed using a photonic chip that directs light from a fibre network to the ions, providing individual phase, frequency, and amplitude control with cross-talk below the 10−3 level [3]. By applying just one of the Raman tones, we
induce an AC Stark shift in the quadrupole transition from S1/2 → D5/2 and use this to demonstrate selective shelving of individual qubits. This enables individual addressing for all coherent operations, as well as state preparation and measurement, thus enabling mid-circuit measurements and in-sequence cooling.
[1] D. Allcock et al., Applied Physics Letters, vol. 119, p. 214 002, 2021.
[2] I. Moore, W. Campbell, E. Hudson, M. Boguslawski, D. Wineland, and D. Allcock, Phys. Rev. A, vol. 107, p. 032 413, 3 2023.
[3] A. Sotirova, B. Sun et al., “Low cross-talk optical addressing of trapped-ion qubits using a novel integrated photonic chip,” arXiv preprint arXiv:2310.13419, 2023.
Uniquely for barium, qubits implemented in either the ground S1/2 level or metastable D5/2 level can be coherently manipulated via a two-photon Raman process using 532nm light with very low scattering error [2]. Individual qubits are addressed using a photonic chip that directs light from a fibre network to the ions, providing individual phase, frequency, and amplitude control with cross-talk below the 10−3 level [3]. By applying just one of the Raman tones, we
induce an AC Stark shift in the quadrupole transition from S1/2 → D5/2 and use this to demonstrate selective shelving of individual qubits. This enables individual addressing for all coherent operations, as well as state preparation and measurement, thus enabling mid-circuit measurements and in-sequence cooling.
[1] D. Allcock et al., Applied Physics Letters, vol. 119, p. 214 002, 2021.
[2] I. Moore, W. Campbell, E. Hudson, M. Boguslawski, D. Wineland, and D. Allcock, Phys. Rev. A, vol. 107, p. 032 413, 3 2023.
[3] A. Sotirova, B. Sun et al., “Low cross-talk optical addressing of trapped-ion qubits using a novel integrated photonic chip,” arXiv preprint arXiv:2310.13419, 2023.
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Publication: A. Sotirova, B. Sun et al., "Low cross-talk optical addressing of trapped-ion qubits using a novel integrated photonic chip," arXiv preprint arXiv:2310.13419, 2023.
Presenters
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Jamie D Leppard
University of Oxford
Authors
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Jamie D Leppard
University of Oxford
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Ana S Sotirova
Oxford Ionics and University of Oxford, Department of Physics, University of Oxford
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Andres Vazquez Brennan
University of Oxford
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Sophie M Decoppet
University of Oxford
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David P Nadlinger
University of Oxford
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Fabian Pokorny
University of Oxford
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Christopher J Ballance
Oxford Ionics and University of Oxford, University of Oxford