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DOE OSTI · 2280975

Angle-robust two-qubit gates in a linear ion crystal

Jia, Zhubing·Huang, Shilin·Kang, Mingyu·Sun, Ke·Spivey, Robert F.·Kim, Jungsang·Brown, Kenneth R.
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Abstract

In trapped-ion quantum computers, two-qubit entangling gates are generated by applying spin-dependent force which uses phonons to mediate interaction between the internal states of the ions. To maintain high-fidelity two-qubit gates under fluctuating experimental parameters, robust pulse-design methods are applied to remove the residual spin-motion entanglement in the presence of motional mode-frequency drifts. Here we propose an improved pulse-design method that also guarantees the robustness of the two-qubit rotation angle against uniform mode-frequency drifts by concatenating pulses with opposite sensitivity of the angle to mode-frequency drifts. Here we experimentally verify significantly improved robustness of the rotation angle against uniform mode-frequency drifts, as well as observe an improvement in gate fidelity from 97.84(10)% to 98.11(11)%, compared to a single frequency-modulated pulse.

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71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

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Jia, Zhubing, Huang, Shilin, Kang, Mingyu, Sun, Ke, Spivey, Robert F., Kim, Jungsang, Brown, Kenneth R.. 2023-03-23. Angle-robust two-qubit gates in a linear ion crystal. https://doi.org/10.1103/physreva.107.032617

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