By Emma Thompson
Publication Date: 2026-08-12 00:30:00
IBM and researchers at the University of Chicago have completed a logical quantum computation that they say exceeded the practical reach of leading classical simulators while providing statistical evidence that the result was accurate.
The experiment used 70 logical qubits to execute 2,415 logical two-qubit operations and 468 logical T gates. According to the researchers, the encoded computation achieved effective logical error rates 10 times lower than the system’s physical error rates.
Their paper, Sampling hard circuits with verifiably high fidelity, sets out an approach designed to address a persistent problem in demonstrations of quantum advantage: how to verify a result once the computation has become too difficult for a classical computer to reproduce efficiently.
Previous experiments have commonly used random circuit sampling, or RCS, which asks a quantum computer to generate complex patterns that classical systems cannot efficiently replicate. As the task becomes harder,…
