This morning, Google researchers officially made computing history. Or not, depending on whom you ask.

The tech giant announced it had reached a long-anticipated milestone known as “quantum supremacy” — a watershed moment in which a quantum computer executes a calculation that no ordinary computer can match. In a new paper in Nature, Google described just such a feat performed on their state-of-the-art quantum machine, code named “Sycamore.” While quantum computers are not yet at a point where they can do useful things, this result demonstrates that they have an inherent advantage over ordinary computers for some tasks.

Yet in an eleventh-hour objection, Google’s chief quantum-computing rival asserted that the quantum supremacy threshold has not yet been crossed. In a paper posted online Monday, IBM provided evidence that the world’s most powerful supercomputer can nearly keep pace with Google’s new quantum machine. As a result, IBM argued that Google’s claim should be received “with a large dose of skepticism.”

So why all the confusion? Aren’t major milestones supposed to be big, unambiguous achievements? The episode reminds us that not all scientific revolutions arrive as a thunderclap — and that quantum supremacy in particular involves more nuance than fits in a headline.

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