Superconducting Ion Trap System for 87Sr+ Hyperfine Qubit

7 Sept 2026, 15:45
20m
Short Talk (15min) Quantum Information & Computing Quantum Computing

Speaker

Qifeng Lao (Komaba Institute for Science (KIS), The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan)

Description

Large-scale trapped-ion quantum processors require highly integrated control architectures capable of supporting high-fidelity gate operations. An all-electronic control platform offers significant advantages in on-chip integration, scalability, and operational fidelity. Recently, a near-field gradient-based entangling method has demonstrated the highest two-qubit gate fidelity among all quantum computing platforms [1].
To date, the near-field gradient required for entangling operations is typically generated by alternating currents flowing through normal-metal trap electrodes. The maximum current that can be applied is constrained by Joule heating in the narrow trap electrodes and the associated power limits required to prevent chip damage. This limitation not only restricts the achievable gate speed but also presents a significant challenge for scaling to large systems, where tens to hundreds of traps may be integrated on a single chip, as the total power dissipation becomes substantial.
To address this challenge, we have demonstrated a full-superconducting surface ion-trap design incorporating a high-Q microwave resonator that generates sub-ampere oscillating currents with sub-milliwatt input power [2]. Furthermore, hyperfine splitting in trapped ions enables qubit encoding in the microwave regime, allowing compact on-chip resonator designs while maintaining long coherence times. Based on these considerations, the 87Sr+ ion is selected as the qubit platform.
In this work, we present the current progress in developing a cryogenic system for a superconducting ion trap based on 87Sr+ ions. This includes the design of a superconducting helical resonator, fabrication of the superconducting ion trap, and the implementation scheme for 87Sr+ ion operation.
[1] A. C. Hughes. et al. arXiv:2510.17286 [quant-ph] (2025)
[2] Y. Tsuchimoto, et al. EPJ Quantum Technol., 11 1 (2024) 56

Academic level PhD student

Author

Qifeng Lao (Komaba Institute for Science (KIS), The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan)

Co-authors

Prof. Atsushi Noguchi (1. Komaba Institute for Science (KIS), The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan 2.RIKEN Center for Quantum Computing (RQC), Wako, Saitama 351-0198, Japan 3.Inamori Research Institute for Science (InaRIS), Organization, Kyoto-shi, Kyoto 600-8411, Japan) Dr Ippei Nakamura (Komaba Institute for Science (KIS), The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan)

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