New Technique Reduces Qubit Leakage by 98.4%, Enhancing Quantum Error Correction

• •QuTech achieved a 98.4% reduction in qubit leakage during measurement.
• •The leakage reduction unit operates without adding time to the measurement process.
• •The LRU maintains a fidelity of 99.2% while suppressing logical error rates.

Researchers at QuTech, Delft University of Technology, have developed a leakage reduction unit (LRU) that achieves a 98.4% reduction in qubit leakage during measurement, significantly improving quantum error correction (QEC) processes. This leakage, which occurs when quantum information escapes the computational state, introduces errors that complicate QEC with superconducting qubits. The LRU operates concurrently with transmon measurement and utilizes a protocol adapted from double-drive reset of population (DDROP), maintaining a high fidelity of 99.2% in assigning computational states. The integration of LRU with neural-network decoding has successfully suppressed logical error rates in both memory and stability QEC experiments without post-selection. This advancement is a crucial step toward building more reliable and scalable quantum computers, addressing a fundamental source of error at its origin. The findings promise to enhance the stability and scalability of future quantum systems.