IBM quantum computer solves intractable problem in 15 minutes

IBM and University of Chicago researchers have demonstrated quantum advantage by solving a computationally intractable problem in approximately 15 minutes—a task that would demand prohibitive amounts of time using leading classical computing methods. The breakthrough, announced July 30, 2026, marks a significant step forward in making quantum computers trustworthy and practical for real-world applications.

The experiment encoded 70 logical qubits—quantum bits that are protected from errors through a specialized encoding scheme—and executed 2,415 logical two-qubit operations and 468 logical “T gates,” both measures of circuit complexity. The system achieved effective logical error rates 10 times lower than the underlying physical error rates, allowing the quantum computer to maintain unusually high accuracy even while performing a large number of operations.

Quantum computers have long promised to outperform classical machines on specific tasks, but verifying that they actually deliver correct answers has proven enormously difficult. As computational problems grow harder, checking whether a quantum computer solved them correctly becomes increasingly infeasible using conventional methods. IBM and University of Chicago researchers addressed this fundamental challenge by developing a structured alternative to the standard random circuit sampling benchmark. Their approach retains the same computational hardness—meaning the problem remains extremely difficult for classical computers—while allowing errors to be detected during the quantum computation itself.