John Clarke, Michel H. Devoret, and John Martinis built an electrical circuit-based oscillator on a microchip.
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2025 Nobel Prize in Physics awarded for macroscale quantum tunneling
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While I'm not sure how to test it yet, I told my girlfriend we were a superconducting Cooper pair and she just rolled her eyes at me :')
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From the article:
"Imagine that an electron is a water wave trying to surmount a tall barrier. Unlike water, if the electron's wave is shorter than the barrier, there is still a small probability that it will seep through to the other side."
I'm a (retired) physicist and still I've been trying to understand what this statement is trying to say. My best guess is that it's making an analogy to a water wave's max height being lower than the barrier, but the water still gets through the barrier. A more correct statement would address the energy of the electron wave vs. the height of the energy barrier.
Since an electron wave doesn't have a height that is measured in terms of distance, the wording here is a rather confusing.
"Imagine that an electron is a water wave trying to surmount a tall barrier. Unlike water, if the electron's wave is shorter than the barrier, there is still a small probability that it will seep through to the other side."
I'm a (retired) physicist and still I've been trying to understand what this statement is trying to say. My best guess is that it's making an analogy to a water wave's max height being lower than the barrier, but the water still gets through the barrier. A more correct statement would address the energy of the electron wave vs. the height of the energy barrier.
Since an electron wave doesn't have a height that is measured in terms of distance, the wording here is a rather confusing.
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Well, this is testable. Do the two of you have opposite spins? When dancing, perhaps? Are your momenta also opposing? We will take it as given that there's an attraction between the two of you, but is it somehow transmitted by vibrations [*]? If it's a yes to all of those, congratulations, you're Cooper-paired up.
[*] For "standard" low temperature superconductors of the sort discussed in the article, the pairing mechanism is mediated by lattice phonons, essentially quantized mechanical vibrations. High-Tc materials are ...different.
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Wait, are there actually useful applications for qubits yet? Do those quantum accelerometers use them perhaps?
I'm not counting "further research" as useful here.
I'm not counting "further research" as useful here.
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It's "kronor" (or "crowns" if translated), not "kroner".
Or just use "SEK", which is the ISO 4217 designation.
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There is no useful quantum computer yet. But SQUIDs amplifiers, magnetometers, and josephson junction array voltage references do have lots of applications. While this Nobel was undoubtedly influenced by the current quantum computing frenzy, the specific work being recognized is broader than that.
SQUIDs and josephson junctions predate the work, but they were the first to show macroscopic coherent tunneling in a squid.
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I was wondering why "John Clarke" sounded so familiar then I saw his picture and read he was at Berkeley, and I realized he was one of my undergrad professors back in ~2004/2005.
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Interesting. I would like to understand quantum physics better but sadly the if-then was far too deeply entrenched in the folds of my brain when news of this type of work reached it. Perhaps in a timeline with a better understanding of quantum phenomena and less fascists that is happening now.
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Did it tunnel into another environment or beyond the environment?
(for those not following: View: https://www.youtube.com/watch?v=3m5qxZm_JqM )
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I'm just picturing a moron repeating "beautiful electrons. Best electrons in the world"
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OT I know, but in general, are the folks that actually award the Nobel as smart as the people who win the award? You'd have to be I would think to fully understand the science and application.
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I will try.
Quantum tunnelling is a consequence of the wave nature of particles. The wave function describing a particle has some non zero width. This means when it is up against a thin enough barrier there is a small probability that it's actually on the other side, even if it wouldn't have enough energy to get through it.
That's plain old tunneling and it's been known since the early days of quantum mechanics. A very simple example of it is a partial mirror. Light can't propagate in metal films, but if you make it thin enough you get partial transmission.
Tunneling is also responsible for some nuclear decay processes. You can make a simplistic model of a uranium nucleus as having an alpha particle bouncing around inside of it. But very occasionally that alpha particle can tunnel out of range of the strong nuclear force that was binding it and it escapes.
All that was understood for a long time for sub atomic particles. What Martinis, Devoret, and Clarke showed was that the state of a superconductor, which is a collective behavior of ~10^20 electrons also behaved quantum mechanically. The collective motion of all those electrons acts like a single particle with discrete energy levels based on the size of the superconducting island. Also those states can tunnel across a barrier just like the subatomic particles people were used to.
It's was a significant technical achievement and led to a bunch of other advances. But perhaps more importantly it also helped trigger a significant mental shift in how we thought about quantum mechanics. It meant that we could make custom quantum systems with parameters defined by lithographic processing.
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Science is like NP-complete problems. It's easier to understand and recognize good work than to create it. That's why college freshmen can learn things that the most knowledgeable scientists from a hundred years ago struggled with. Of course you still have to be knowledgeable and you need to study, but it's not like everyone is shocked by their choices most years.
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You succeeded. I feel like I understand it now. Until tomorrow, anyway.
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I think the real world impact of their discovery was more in how it influenced the continued shrinking of transistors. Without understanding macroscopic quantum tunneling we likely would have hit a wall all the way back when high k dielectrics were the big news in wafer tech (~2007-2008 for commercialization)
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When I saw the first name of the winners, I thought it must be something to do with materials and making sure the front doesn't fall off.
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It's trying to explain the concept to idjits like me who don't know anything. It's saying that the electrons can cross barriers in way we'd naively think it shouldn't. For a pop-sci article, at least based on context, it appears to be fine.
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The selection committee are all physics professors who are members of the Royal Swedish Academy of Science and elected by their peers to serve on the committee. You don’t have to be as smart as an actual laureate to know what has been an important finding in your field, though. You just have to be well-versed in your field.
https://www.nobelprize.org/about/the-nobel-committee-for-physics/
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My knowledge of quantum mechanics begins and ends with Heisenberg, plus a very minimal amount of QED and QCD, so a lot of the theory behind these "macroscale quantum phenomena" flies straight over my head.
Luckily I did not need a complete grasp of the theory to determine that the little electrons in the explanatory diagram are very cute and charming. Look at those li'l guys! So much confusion, just vibrating away at random! Then they look so happy once they pair off! Feels vaguely familiar for some reason...
Luckily I did not need a complete grasp of the theory to determine that the little electrons in the explanatory diagram are very cute and charming. Look at those li'l guys! So much confusion, just vibrating away at random! Then they look so happy once they pair off! Feels vaguely familiar for some reason...
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Thanks for this; I was wondering about what was meant by the following quote from the article, and your explanation sums it up nicely.
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While I'm only able to understand a fraction of the work of these researchers, the illustration of these confused electrons in a tube really struck me ; they're cool little buddies and I wish for more scientific articles to have them!
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Terrific job in explaining in such simple terms.
Even though I think I know this stuff, I always struggle in putting it in such simple terms which tells me I don't know it half as well as I think I do.
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I had him for undergrad quantum mechanics (I think) in the mid to late '80s, around the time he was doing this work. He was a good teacher (teacher of the year at some point, IIRC?). I remember talk of SQUIDs, which I thought was some kind of niche thing with a weird name--I had no idea he was doing work that would win him a Nobel Prize.
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John Clarke was one of my thesis advisors - genuinely one of the nicest, most knowledgeable and most invested academics I interacted with during my time @ Berkeley. Couldn't have happened to a better guy, I was ecstatic when I found out about this news.
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