Researchers from Google Quantum AI report that their quantum processor, Willow, ran an algorithm for a quantum computer that solved a complex physics problem thousands of times faster than the world’s most powerful classical supercomputers. If verified, this would be one of the first demonstrations of practical quantum advantage, in which a quantum computer solves a real-world problem faster and more accurately than a classical computer.
In a new paper published in the journal Nature, the researchers provided details on how their algorithm, called Quantum Echoes, measured the complex behavior of particles in highly entangled quantum systems. These are systems in which multiple particles are linked so that they share the same fate even when physically separated. If you measure the property of one particle, you instantly know something about the others. This linkage makes the overall system so complex that it is difficult to model on ordinary computers.
The Quantum Echoes algorithm uses a concept called an Out-of-Time-Order Correlator (OTOC), which measures how quickly information spreads and scrambles in a quantum system. The researchers chose this specific measurement because, as they state in the paper, “OTOCs have quantum interference effects that endow them with a high sensitivity to details of the quantum dynamics and, for OTOC(2), also high levels of classical simulation complexity. As such, OTOCs are viable candidates for realizing practical quantum advantage.”
The algorithm relies on a clever “time-reversal trick.” The quantum computer runs the system forward, gives it a little nudge, and then precisely reverses the process. In this experiment, they used the second-order OTOC—OTOC(2), a more complex form of OTOC. This creates a strong “quantum echo” that extracts useful information from the system’s chaos. For this task, which was to study how fast information spreads in a complex quantum state, the quantum chip performed the calculation 13,000 times faster than the world’s fastest supercomputer.
This isn’t the first time the Google team has demonstrated a major quantum feat. In 2019, they claimed “quantum supremacy” after their Sycamore chip solved a highly technical problem much faster than a supercomputer. However, what makes this different is that while the previous experiment focused on solving an obscure problem (which was ultimately solved by classical algorithms running on supercomputers), this new result solves a real-world physics problem.
Ultimately, what this research means is that we could be edging closer to a day when quantum computers are regularly used to solve complex problems that are currently beyond the reach of supercomputers. This could include discovering new materials, designing better drugs and creating more precise climate models.
Written for you by our author Paul Arnold, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive.
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More information:
Observation of constructive interference at the edge of quantum ergodicity, Nature (2025). DOI: 10.1038/s41586-025-09526-6
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Google claims its latest quantum algorithm can outperform supercomputers on a real-world task (2025, October 24)
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