Quantum error correction avoids pausing with new hardware design

Yuejie Xin and colleagues have demonstrated a leakage reduction unit (LRU) achieving 98.4% leakage removal during qubit measurement without adding time overhead, a critical step for improving quantum error correction. Adapted from a protocol called DDROP, the LRU utilizes simultaneous drives on the transmon and its readout resonator, actively returning qubits to a usable state. The LRU achieves a 98.4% leakage removal fraction without compromising the 2RO assignment fidelity (99.2%). The team combined this enhanced measurement with neural-network decoding to successfully suppress logical error rates in experiments with up to nine qubits. A 98.4% leakage removal fraction was experimentally achieved without adding any time overhead to the standard two-level readout process, a critical advancement for scaling quantum error correction in superconducting circuits. This improvement stems from a newly developed Leakage Reduction Unit (LRU) integrated directly into the qubit measurement process, circumventing the need for additional processing steps that typically slow down computations. The LRU operates by simultaneously applying microwave pulses to both…