Qubit reset experiment removes leakage during measurement without added time

Researchers demonstrated a method that returned superconducting qubits from an unusable state during measurement without extending the standard two-level readout process. Their leakage reduction unit removed 98.4% of leakage while maintaining 99.2% readout assignment fidelity, according to the reported experiments. The method applies microwave drives to a qubit and its readout resonator at the same time. Paired with a neural network that interprets measurement results, it helped suppress logical errors in tests using up to nine qubits. The strongest reported error correction used three-level readout, whose assignment fidelity was 96.3%.