Spectator Leakage Suppression via Invariant Subspace Engineering for CZ Gates in Superconducting Quantum Circuits
An arXiv preprint proposes an invariant subspace engineering method to suppress spectator leakage during controlled-Z gates in superconducting quantum circuits. The approach targets unwanted transitions in non-target qubits during two-qubit operations. The authors report suppression of leakage to higher excited states in spectator qubits.
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What this could mean
- 0–2 yearsPlausible
This could enable fixed-frequency transmon architectures to achieve higher two-qubit gate fidelities by reducing a dominant coherent error source, potentially improving near-term error correction experiments.
Spectator leakage is a known source of correlated errors that limits gate fidelity in multi-qubit superconducting chips. If the proposed invariant subspace engineering is implementable with existing microwave control and calibration, it could be integrated into standard gate optimization workflows within two years.
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