In an experimental demonstration using a superconducting processor named Zuchongzhi 3.2, China announced a significant breakthrough in quantum error correction, dubbed “quantum supremacy 2.0.”
The Zuchongzhi 3.2 processor successfully exploits a surface-coded logic qubit at a distance of 7.
The remarkable factor is that as the code distance increases, the logical error rate decreases. This inverse relationship is a key aspect of China’s latest quantum error correction technique, which rivals Google’s earlier results with its Willow results.
What sets China’s claims apart is an all-microwave leak suppression architecture designed to minimize “leaks,” in which qubits escape the computational states assumed by error-correcting codes.
Addressing leaks is crucial because they can lead to correlated failures that traditional set-top boxes struggle to handle. This new method makes leakage control a vital design consideration, as previous research has also highlighted its importance in maintaining clean surface code cycles.
Although China’s results aim to match Google’s benchmarks, they do not yet demonstrate the ability to run large calculations across multiple interacting logical qubits.
The transition from a single logical qubit to multiple logical qubits results in complex engineering challenges and new error pathways.
IBM’s roadmap highlights that scaling to practical fault suppression systems will require efficient codes and real-time decoding pipelines.
As the industry embraces the “age of error correction,” the focus is now on making error correction repeatable, automatable, and economically scalable.
As several groups achieve subthreshold behavior, the next challenge should be to stack logical qubits efficiently and maintain manageable error budgets during actual calculations.
