Special CPM Seminar

Quantum error correction below the surface code threshold

Alexandre Bourassa

Google Quantum

Quantum error correction (QEC) is critical for achieving useful quantum computers, since it allows us to combine many noisy physical qubits into one high-quality logical qubit with exponentially decreasing logical error rate. Here [1] we demonstrate below threshold surface code experiment with logical qubits at distances=(3, 5, 7), where errors are more than halved for each increase in distance. Additionally, we report the ability to decode these QEC experiments in real-time for 1 million rounds. Finally, we present a 10,000x reduction in the rare correlated errors by measuring the repetition code in the very low error regime. Ultimately, our results present device performance that, if scaled, could realize the operational requirements of large scale fault-tolerant quantum algorithms.

[1] Quantum error correction below the surface code threshold, Google Quantum AI, arXiv:2408.13687 (2024)