r/computerscience • u/National-Dragonfly35 • 3d ago

IBM quantum computer solves classically intractable problem in 15 minutes

https://www.sciencedaily.com/releases/2026/08/260829035219.htm

"The researchers showed that their method preserves the same computational hardness criteria associated with RCS, meaning the problem remains extremely difficult for classical computers. At the same time, the added structure allows errors to be detected during the quantum computation."

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u/Cryptizard 3d ago

Keep in mind that RCS here stands for random circuit sampling. That means that the intractable problem in question is “give me the output when you run this random circuit on a quantum computer.” It is designed to be maximally advantageous for quantum computers compared to classical computers, not for it to have any practical value.

That said, it is a baseline test to check whether a quantum computer is doing anything interesting (think of it like a hardware validation) and this paper does go farther than previous research in terms of number of qubits and error correction.

They also have some neat new ideas about circuit families and complexity arguments, but it’s all just kind of inside baseball for quantum computing folks. Nothing revolutionary for the outside world.

I do wish that popular news would stop picking up these results and taking them way out of context because it definitely gives people the wrong impression about quantum computing.

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u/Aaron1924 2d ago

Nitpick: RCS is not completely useless, e.g. it can be used to generate certified random numbers as described in this Nature paper

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u/Cryptizard 2d ago

That’s not really practically interesting. It takes an ungodly amount of classical verification on the client side, and every client has easy access to randomness themselves, in practice.