Caltech Quantum Frontiers

Has Quantum Advantage Been Achieved?

The blog post examines whether quantum advantage has truly been achieved, noting that less than half of a physics‑focused audience believed it had. It defines quantum advantage as a programmable quantum device solving a specific task faster than any classical computer, with random circuit sampling (RCS) serving as the standard benchmark. The author reviews major RCS experiments—Google’s 53‑qubit Sycamore, USTC’s 56‑83‑qubit superconducting processors, and Quantinuum’s 56‑qubit trapped‑ion system—highlighting their XEB scores and the difficulty of classical replication. Finally, the post discusses the reliance on proxy metrics and the ongoing debate about the strength of the evidence.