Entangling gates between high-Q cavity qubits using an erasure-detected dual-rail ancilla
Oral-In-person · Withdrawn
Abstract
Converting dominant gate errors into erasures - errors that are detected and located - can improve the effectiveness of quantum error correction (QEC) [1].
In bosonic cavity qubits, errors primarily originate from the noisy, nonlinear ancilla used to control the cavity modes. We introduce a dual-rail [2,3] ancilla qubit for cavity control that converts dominant ancilla-induced errors into flagged erasures while suppressing residual Pauli errors. Combined with the long lifetimes of our 3D microwave cavities [4] and a long-coherence erasure-detected ancilla, this approach can support high gate fidelities when post-selecting runs without erasure flags. We present progress toward a high-fidelity entangling gate between cavity modes, paving a path to operations in bosonic qubits with built-in protection against ancilla errors.
[1] QCI, (2025). Bias-preserving and error-detectable entangling operations in a superconducting dual-rail system arXiv, https://arxiv.org/pdf/2503.10935
[2] Kubica, A. et al.(2023). Erasure qubits: Overcoming the T₁ limit in superconducting circuits. Physical Review X, 13(4), 041022. https://doi.org/10.1103/PhysRevX.13.041022
[3] Levine, H. et al. (2024). Demonstrating a long-coherence dual-rail erasure qubit using tunable transmons. Physical Review X, 14(1), 011051. https://doi.org/10.1103/PhysRevX.14.011051
[4] Milul, O. et al. (2023). Superconducting cavity qubit with tens of milliseconds single-photon coherence time. Physical Review X Quantum, 4(3), 030336. https://doi.org/10.1103/PRXQuantum.4.030336
In bosonic cavity qubits, errors primarily originate from the noisy, nonlinear ancilla used to control the cavity modes. We introduce a dual-rail [2,3] ancilla qubit for cavity control that converts dominant ancilla-induced errors into flagged erasures while suppressing residual Pauli errors. Combined with the long lifetimes of our 3D microwave cavities [4] and a long-coherence erasure-detected ancilla, this approach can support high gate fidelities when post-selecting runs without erasure flags. We present progress toward a high-fidelity entangling gate between cavity modes, paving a path to operations in bosonic qubits with built-in protection against ancilla errors.
[1] QCI, (2025). Bias-preserving and error-detectable entangling operations in a superconducting dual-rail system arXiv, https://arxiv.org/pdf/2503.10935
[2] Kubica, A. et al.(2023). Erasure qubits: Overcoming the T₁ limit in superconducting circuits. Physical Review X, 13(4), 041022. https://doi.org/10.1103/PhysRevX.13.041022
[3] Levine, H. et al. (2024). Demonstrating a long-coherence dual-rail erasure qubit using tunable transmons. Physical Review X, 14(1), 011051. https://doi.org/10.1103/PhysRevX.14.011051
[4] Milul, O. et al. (2023). Superconducting cavity qubit with tens of milliseconds single-photon coherence time. Physical Review X Quantum, 4(3), 030336. https://doi.org/10.1103/PRXQuantum.4.030336
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Presenters
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Eyal Dar
- Weizmann Institute of Science