IBM quantum computer solves classically intractable problem in 15 minutes

August 30, 2026 at 05:00 AM1 min

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IBM and University of Chicago researchers used a new error correction strategy to encode 70 logical qubits and solve a classically intractable problem in about 15 minutes. The experiment met key criteria for quantum advantage, performing a calculation beyond the practical reach of leading classical simulation while providing evidence of a reliable result.

Key Facts

The quantum computation was completed in about 15 minutes, while leading classical methods would require an impractical amount of time.
The experiment encoded 70 logical qubits using a newly designed form of encoded quantum circuit.
The circuits and experimental results have been made publicly available through the Quantum Advantage Tracker.
The work is described in a paper titled "Sampling hard circuits with verifiably high fidelity."

Verification Challenge

Random circuit sampling (RCS) has long been used to test whether quantum computers can outperform conventional machines. Once a quantum calculation becomes too difficult for a classical computer to reproduce, verifying the result becomes increasingly difficult. The IBM and University of Chicago team developed a more structured alternative to RCS that preserves computational hardness while allowing error detection during the quantum computation.

Researcher Statements

Bill Fefferman, Associate Professor at the University of Chicago, said verification remains one of the biggest challenges in firmly establishing experimental quantum advantage. Fefferman added that the experiment develops techniques to better characterize the fidelity of hard quantum states under noise. Soumik Ghosh, PhD student in Fefferman's group, said advances in verification have the potential to unlock practical applications for the next generation of quantum computers.