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Imagine a computer that could solve incredibly complex problems at a speed we can't yet fathom and bring about breakthroughs in fields like drug development or clean energy. That is widely considered the promise of quantum computing. In 2025, tech companies poured money into this field. The Trump administration also named quantum computing as a priority. But when will this technology actually deliver something useful for regular people? NPR's Katia Riddle reports on the difference between quantum hype and quantum reality.
KATIA RIDDLE, BYLINE: Tech companies like Google and Microsoft, as well as the U.S. government, bet big on quantum computing in 2025.
(SOUNDBITE OF MONTAGE)
UNIDENTIFIED PERSON #1: Google Quantum AI is unveiling the first demonstration of verifiable quantum advantage.
PRESIDENT DONALD TRUMP: Joining forces on quantum computing.
UNIDENTIFIED PERSON #2: Creating an entirely new architecture for quantum computing.
RIDDLE: Bill Fefferman, a professor and computer scientist at the University of Chicago, is not quite as enthusiastic.
BILL FEFFERMAN: While I think there's been a lot of exciting progress toward building large-scale quantum computers, we've not yet seen a quantum experiment that both solves a problem that's provably hard and also is independently useful for society.
RIDDLE: Fefferman got into this field because he found it so fascinating. He still does. In the decade or so he's been working in quantum computing, it's grown beyond anything he could imagine. But he says it's still unclear if it will deliver practical value in his lifetime.
FEFFERMAN: I would say the jury's still out.
RIDDLE: Even Google, while bragging about its achievements, is simultaneously managing expectations. Here's a recording from one of its marketing videos called "Quantum Computing: Hype Versus Reality."
(SOUNDBITE OF ARCHIVED RECORDING)
UNIDENTIFIED PERSON #3: So a useful, large-scale, error-corrected quantum computer that solves lots of practical, real-world problems is still a ways off.
RIDDLE: So why the continued frenzy over quantum computing, even if it's not delivering? To answer this question, let's look at one key phenomenon underlying quantum theory - superposition.
(SOUNDBITE OF TED TALK)
DOMINIC WALLIMAN: I can spin around one way. I can spin around the other way.
RIDDLE: Dominic Walliman is a scientist and educator whose job it is to explain stuff like this. Here is part of his Ted Talk called "Quantum Physics For 7-Year-Olds." In this part of the lecture, he's standing on the stage explaining superposition. That's when a particle's state isn't fixed. It exists in a combination of possible states. It's a cloud of probabilities. He turns the other way.
(SOUNDBITE OF TED TALK)
WALLIMAN: But what would it look like for me to spin around in both directions at the same time?
RIDDLE: Walliman wiggles around like he's caught between two opposing forces.
(SOUNDBITE OF TED TALK)
WALLIMAN: We can't do that (laughter). We can't imagine that. But this is what these subatomic particles do all the time.
RIDDLE: Regular computers can think only in binary - black or white, zero or one. Quantum computers use superposition to think in shades of gray, in terms of potentials and possibilities and actually simulate the way molecules work in nature. The whole project of quantum computing is to harness this power. Charina Chou is the COO at Google Quantum AI. She says the promise for quantum computing is almost limitless.
CHARINA CHOU: There are numerous diseases that are unsolved - right? - for which there are no cures, for which the medicines have terrible side effects or, you know, we just don't have a full answer.
RIDDLE: So far, these use cases are still just fantasies, but big fantasies.
CHOU: Either factories or agriculture or other places where small molecules matter, extended solid-state materials that might be used in batteries or semiconductors, things like that.
RIDDLE: To be clear, the early prototypes of quantum computers look nothing like your laptop. They're huge, for one thing - the size of refrigerators - and they're kept at extremely cold temperatures. Right now, scientists are working towards the basic goal of getting these computers to solve an algorithm that a regular computer couldn't in a reasonable amount of time. That's something called quantum supremacy. Chou says Google already delivered this in 2019 with a computer chip they named Sycamore.
CHOU: It showed, all right, on our best quantum chip, it would take a couple of minutes to solve this random circuit sampling benchmark problem, and it would take 10,000 years on the world's best supercomputer.
RIDDLE: A couple minutes to solve a problem that would otherwise take 10,000 years does represent a tremendous accomplishment. Bill Fefferman, the quantum scientist, says this is part of the reason he's skeptical.
FEFFERMAN: Problem is is that we don't have proofs of those sorts of numbers.
RIDDLE: It's such a new field, he says, it's hard to predict anything with accuracy. In fact, shortly after Google made this claim, IBM said they could do the same calculation with a classical computer in a couple of days. Google, today, stands by their results, pointing out that IBM's claim was theoretical. Fefferman stresses that advances from Google and others should be seen as progress, not failure, even if they are later disproven.
FEFFERMAN: It's not a failure. Actually, these claims - it's not clear at all that they're not correct when they come out.
RIDDLE: It's the job of people like him and his colleagues, he says, to kick the tires on these kinds of experiments and help build better quantum computers.
FEFFERMAN: Then everything improves because the next experiment gets better.
RIDDLE: Fefferman says it could be five years or a hundred years or 20 years until we see a quantum computing breakthrough. But he emphasizes how far the field has come since he started in it after earning his Ph.D. in 2014.
FEFFERMAN: We thought we were working on sort of science fiction experiments. Like, we didn't even think that this would ever come close to fruition.
RIDDLE: Fefferman says the most realistic goal of quantum computing right now is progress for its own sake. That's how science works, even when it feels like science fiction.
Katia Riddle, NPR News. Transcript provided by NPR, Copyright NPR.
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