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.
“Verification remains one of the biggest challenges in firmly establishing experimental quantum advantage,” said Bill Fefferman, associate professor at the University of Chicago and co-author of the paper. “This experiment develops techniques to better characterize the fidelity of hard quantum states under noise, increasing confidence that the quantum computer is solving a computationally hard problem.”
The demonstration represents one of the largest error-correction experiments conducted to date. Quantum error correction works by encoding quantum information across multiple physical qubits in a way that protects the information from environmental interference and computational errors. The IBM team’s ability to scale this approach to 70 logical qubits while reducing error rates by a factor of 10 shows that error correction can improve reliability as systems grow larger—a critical requirement for practical quantum computing.
The milestone echoes earlier quantum computing claims but with a crucial difference. In 2019, Google announced quantum supremacy using its 53-qubit Sycamore processor, which performed a random circuit sampling task in about 200 seconds. That demonstration sparked ongoing debate about whether the result could be verified and whether it had practical value. The IBM-Chicago experiment directly addresses those criticisms by demonstrating both computational hardness and verifiable accuracy simultaneously—establishing what researchers call “trusted quantum computation.”
Jay Gambetta, director of IBM Research and IBM Fellow, stated: “We are now firmly in the quantum advantage era. We have demonstrated a quantum computation beyond the practical reach of classical computers that establishes, with statistical confidence, a lower bound on how faithfully it was executed. This milestone gives scientists, developers, and businesses a new foundation for trusting quantum computers as they scale to problems far beyond what we can achieve classically.”
Error correction and trustworthy verification are considered essential for scaling quantum computers toward solving practical problems in drug discovery, materials science, optimization, and financial modeling. The demonstration shows that the path to larger, more reliable quantum systems is becoming clearer, though significant engineering challenges remain. IBM has publicly committed to delivering its first fault-tolerant quantum computer—one that can correct errors faster than they accumulate—by 2029, and this result suggests that timeline is achievable.
Sources
- ScienceDaily — IBM quantum computer solves classically intractable problem in 15 minutes; published August 30, 2026, based on IBM and University of Chicago announcement
- Phys.org — Quantum computer completes verified task beyond practical reach of classical simulations; published August 1, 2026, based on University of Chicago research
- IBM Newsroom — IBM and The University of Chicago Demonstrate Quantum Advantage, Establishing Trusted Quantum Computation on Logical Circuits; published July 30, 2026
