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Hey Short Wavers, Emily Kwong here.
So the last Tuesday of every month is Nature Quest.
That's the segment where we take one of your questions about the environment, how it's changing, and investigate it.
We've talked about why flowers are blooming early, how to live with extreme heat, why all the mosquitoes, what is managed retreat, and we are looking for more questions for future episodes in 2026.
So if you're wondering what's going on with planet Earth and the bugs and the birds and the bees around you, email us at shortwave at nprorg.
Give your name, your location, your question.
Bonus points if you record your question as a voice memo.
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Hey, shortwavers.
Emily Kwong here.
And today I am joined by NPR science correspondent, Katia Riddle.
Hey, Katia.
Hi, Emily.
Hi.
Okay.
Today we're talking about quantum, which is one of my favorite topics in science.
Yeah, quantum science and computing.
I think it's safe to say they came up often in science news in 2025.
Yeah.
It used to be a concept that we heard about, you know, like in sci-fi, but this year scientists have been talking about its utility IRL.
Okay, quantum in real life, how so?
Well, for one thing, despite all the slashing and burning the Trump administration has done around science investments this year, quantum computing and science is one of two things that they've pledged to preserve funding in, along with AI.
Yes, AI for sure, too.
When it comes to quantum, there's also been a ton of investment from tech companies, right?
Yeah, exactly.
Billions of dollars both from our government and from China's government, as well as tech companies.
Google, for example, continues to tout breakthroughs that they've made something called quantum supremacy or quantum advantage.
Today, Google Quantum AI is unveiling the first demonstration of verifiable quantum advantage, a critical step that transforms quantum computing from being science into doing science.
Wow.
That little ding at the end really sells it.
Quantum advantage.
They have been bragging a lot about this new quantum computing chip they have called Willow, which they say is an indicator of real progress in the field.
Yeah.
Let's talk about the progress of the field, because the Nobel Prize this year, one of them had to do with working quantum mechanics.
Right.
So 2025 Physics Nobel was awarded jointly to John Clark, Michel Devoret and John Martinez for their work proving a concept called quantum mechanical tunneling.
What is quantum mechanical tunneling?
So it's a fundamental concept of quantum that particles can tunnel their way through barriers that by the conventional rules of physics they shouldn't be able to penetrate.
The work happened a few decades ago, but many people now credit it with laying the foundation for advancements in quantum that have happened since then.
One thing, Katie, I'm wondering, when is quantum going to be a part of my life?
Like, what can it do for regular folks?
Yeah.
What have you done for me lately?
Quantum.
Once you get past the question of what it actually is, the next illogical question when will it actually pay off?
We hear that quantum science and engineering can one day help do things like cure diseases or design new materials, or optimize things like traffic or supply chains or, you know, use cases that we can't even fathom right now.
I talked to a lot of scientists for the story about this question, and even the ones who are working on the front lines of this field are really managing expectations, both theirs and ours, on that question.
Today on the show, is the future really quantum?
And if so, when?
We go beyond the quantum hype to get a sense of where the science really is.
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OK, Katie, let us start with quantum physics itself.
Can you remind me what that is?
Right.
Quantum is the physics of the smallest things, electrons, photons, other subatomic particles.
The wild part is they don't follow the same rules as the stuff that we can see.
Their behavior is weird, but it's consistently weird.
I love Consistently Weird.
And I loved the movie Ant-Man, whose plot was very dependent on this.
I have not seen it, but now I want to.
You should.
It's really good.
What is an example of how subatomic particles behave in weird ways?
One of the concepts you hear a lot is superposition.
That means a particle that can be in multiple potential states at once.
You've heard of Schrodinger's cat, dead and alive.
Like the universe hasn't decided if the cat is dead or alive, until the box containing the cat is open,
It's a cloud of probabilities.
Right.
And in the world of quantum it means superposition, means that particles could be doing many things at once.
Right.
And this is a concept that's been around for a while, almost as long as the whole field that was established 100 years ago, around the time of Niels Bohr and Einstein.
What does this have to do with quantum computing?
How does that fit together?
Yeah.
So what I've been talking about is quantum physics.
The idea with quantum computers is that they can actually use these behaviors.
We humans like to think we're smart, but nature is still much better than us at innovation.
If you can harness quantum to use in computing, then we can accurately simulate the behavior of molecules and subatomic particles.
Yeah.
How does that compare to classical computing paradigms?
Classical computers use bits, zeros and ones.
Everything your computer does is just a big pattern of those.
Quantum computing thinks in something called qubits, which can be zero and one at the same time, in a probabilistic sense.
That's back to that superposition idea.
Right.
This is why people say quantum computers can try out a lot of possibilities all at once.
Exactly.
I went on a mission to find a metaphor to explain quantum computing.
And first of all, let me say there is no perfect metaphor.
But one that I got that was kind of helpful from Dominic Walliman he's a physicist is light switches.
So if you've got a bunch of light switches that turn a bunch of lights on and off all the time.
That's like a normal computer in binary.
It's in one state at a time.
So say you're trying to get your house lit just right.
You might try different combinations of lights on off and in different rooms until you get it just right.
But quantum computers obey different rules.
Quantum computers think in shades of gray.
It's kind of like all of the lights are on, but on a dimmer switch.
So instead of checking every combination of lights one by one like a classical computer...
A quantum computer can represent all those combinations at once as probabilities.
So say you have 20 light switches.
Some are on and some are off.
That's like a classical computer.
In a quantum computer.
You would instead have 20 light switches with dimmers all set to varying degrees of brightness.
Now, this does not mean that quantum computers instantly solve everything.
But that potential parallelism in problem solving is why people are so excited.
Very cool.
Very cool.
Because it's just processing so many things in parallel.
It's significantly more efficient at problem solving.
Question, what do quantum computers actually look like?
Because I can't just swap out my laptop for one.
No, that's going to be a long time until that happens.
Right now, they're huge, like the size of a refrigerator.
Secondly, they are cold, colder than some places in space.
Inside of them is equipment like microwave wires, shielding layers, filters.
And then, at the very bottom, is this quantum processor which carries signals down to the quantum chip.
The quantum chip is what's at the heart of all of this.
Yes, exactly.
It's like a giant onion with a tiny one to two centimeter chip at the very heart of it.
That's all.
Very different than today's computers.
All right.
So, on the matter of expectations, we have heard a lot of big dreams coming from the tech world regarding quantum, that it will cure diseases, solve traffic, design new batteries.
How realistic are those?
Yes.
So many scientists genuinely believe quantum computing could help with things like simulating molecules or developing new materials, because those problems are just incredibly complex, too complex for classical computers.
But another guy I talked to, Bill Pfefferman.
He's focused his life's work on quantum physics and he's pretty skeptical about its actual usefulness.
While I think there's been a lot of exciting progress toward building large-scale quantum computers, one thing that's super important to realize is that we've not yet seen a quantum experiment that both solves a problem that's provably hard and also is independently useful for society.
Bill is a computer scientist at the University of Chicago.
He says the field is still just very early.
We don't have quantum computers that can do useful real-world tasks yet.
Wait, so then where are all these milestones coming from that we hear about from folks like Google?
Right.
Before we can use quantum computing to, for example, cure cancer, we have to make sure that quantum computers we have are accurate.
That is a really, really hard task.
We talked about this idea of quantum supremacy.
That's the idea that a quantum computer solves a problem faster than any classical computer could in a reasonable amount of time.
Yeah.
And that's what Google is claiming to have done with their computer chip.
Yes, Google is claiming to with their computer chip.
I talked to Karina Chow.
She's the COO at Google Quantum AI, and they make this claim.
So Google demonstrated this on a quantum chip in 2019.
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 10000 years on the world's best supercomputers.
Okay, so they solved a problem that would have taken a normal computer 10,000 years accurately.
That is the breakthrough.
Well, it depends on who you talk to.
It would be, but some people disputed this claim.
IBM came out shortly afterward and showed that they had a classical computer solve it in a couple days.
Google stands by their claim.
They argue it still did show quantum supremacy at the time.
So it's debatable how significant these milestones are or not. when they'll yield something useful.
So basically, real progress, unclear payoff timeline.
But then why does the US government and tech companies keep pouring money into this field if it has not yielded anything major yet?
That is something I talked to Bill Pfefferman about.
He, again, is the number one skeptic.
But he underscored that these claims by Google and others, they are milestones.
It's not a failure.
Actually, these claims, it's not clear at all that they're not correct when they come out.
His point was, this is how science works.
We invent something, we kick the tires, we keep inventing.
He started in this field in 2014 after he got his PhD.
And here's where it was at that time.
We thought we were working on sort of science fiction experiments.
We didn't think that this would ever come close to fruition.
So amid his skepticism is genuine excitement for quantum's future.
So bottom line if I'm telling a friend about quantum computing, what is the best, most accurate thing to say right now?
There's consensus that the potential is huge beyond what we can even imagine right now.
But no one knows when we'll see that potential deliver into real world applications.
Could be five years, could be 50, could be something in between.
Katie or Riddle, thank you for taking the Quantum Leap with us today.
Anytime, Emily.
If you enjoyed this episode, short wavers, follow us on the platform you're listening to and check out our episode on quantum clocks.
We'll link it in the show notes.
This episode was produced by Burleigh McCoy.
It was edited by our showrunner, Rebecca Ramirez, and fact-checked by Tyler Jones.
Kweisi Lee was the audio engineer.
Beth Donovan is our vice president of podcasting.
I'm Emily Kwong.
Thank you for listening to Shortwave from NPR.
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