Quantum Computer Solves a Problem in 15 Minutes That Classical Methods Can’t Practically Compute

Researchers have demonstrated a quantum computation that appears to exceed the practical capabilities of leading classical simulation methods while also addressing a longstanding problem: how to verify the result.

A quantum computer completed a difficult calculation in about 15 minutes, while leading classical simulation methods would require prohibitive amounts of time. Just as importantly, the experiment included a way to establish confidence that the quantum result was accurate.

IBM and University of Chicago researchers announced the demonstration on July 30, 2026, presenting it as evidence that quantum computing has met the central requirements for quantum advantage. This means completing a task beyond the practical reach of leading classical methods while providing a reliable measure of how faithfully the quantum computation was performed.

In a paper published on arXiv, the researchers describe a new design for encoded quantum circuits that allowed them to pursue both goals at once. The experiment became one of the largest demonstrations of logical quantum computing reported so far. The circuits and results have also been released publicly through the Quantum Advantage Tracker.