South Korea Hits 99% Two-Qubit Gate Accuracy in Quantum Push

Why the 99% figure matters

The ministry calls entangling-gate accuracy a key indicator of a quantum computer's error rate and says the groundwork is now in place for its goal of a 100-qubit error-corrected superconducting processor by 2029. Outside experts offered a more cautious reading: 99% is roughly the error-correction threshold, and accuracy must eventually reach 99.99% to 99.9999% or higher. They also noted that the overhead of logical qubits grows exponentially as qubit counts rise.

Communication and sensing

In quantum communication, teams reported a solid-state quantum repeater that creates entanglement on demand, an all-photonic repeater that links entanglement using light alone, and patent filings for quantum-light converters. Repeaters are seen as essential for long-distance quantum networks, distributed quantum computing and quantum cryptography.

In sensing, researchers unveiled a compact magnetic field sensor based on nitrogen-vacancy (NV) centres in diamond that can perform magnetocardiography. Unlike conventional equipment, it works at room temperature and can be miniaturised. In medicine, it could detect tiny magnetic changes in the heart without electrodes, helping diagnose conditions such as myocardial ischaemia and arrhythmia.

The government is reportedly preparing to announce a 50-qubit superconducting quantum computer demonstration this month or next.