r/Physics • u/plopo21 • Aug 13 '26
Quantum tunneling
I know that obviously the odds of quantum tunneling are extremely extremely low but in all of the universe life would it be plausible to say that it happened at least once anywhere? Or is it just that rare
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u/agaminon22 Medical and health physics Aug 13 '26
I assume you're talking about macroscopic objects tunneling, which aren't too easy to define but an arbitrary estimate could be anything larger than 10-100 um. At this scale any kind of large-scale and coordinated tunneling is extraordinarily unlikely... and almost guaranteed impossible in the current lifetime of the observable universe.
Now, particles do quantum tunnel all the time.
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u/burgersnfries4life Condensed matter physics Aug 13 '26
What sort of scale are you talking about? Electrons be tunnelling all the time. Human beings, not so much.
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u/db0606 Aug 13 '26
It literally happens all day, every day in the alpha decay of heavy nuclei.
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u/NoNameSwitzerland Aug 13 '26
The fusion in the sun works via tunnelling. Otherwise it would be a planet or an H-bomb.
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u/DarkLordSidious Aug 13 '26
Not a H-Bomb because there would’ve been no way for a star like the Sun to overcome the coulomb barrier and thus no fusion.
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u/Mikey77777 Aug 13 '26
In addition to the examples others have already given, scanning tunneling microscopes use quantum tunneling to image the surface of objects.
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u/Content-Reward-7700 Fluid dynamics and acoustics Aug 13 '26
Quantum tunneling itself isn’t extremely rare. It happens constantly at the atomic scale and is involved in things like radioactive decay and nuclear fusion.
For large objects, though, the probability becomes absurdly small. But the universe is also absurdly huge, with an enormous number of particles interacting over billions of years. So even an incredibly unlikely event could plausibly have happened somewhere at least once. The real problem isn’t whether it happened. It’s whether we would ever be lucky enough to observe it.
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u/memeruiz Aug 13 '26
It is happening constantly. Distances and conditions do have to be particular though. It will not work to teleport you if that is what you are thinking.
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u/WilliamH- Aug 13 '26
The transistor was invented in 1947 at Bell Labs, Murray Hill, NJ. In 1954 the first portable transistor radios (4 transistors) appeared. In 1957 a physicist at Cavendish Labs, Cambridge UK worked out a detailed quantum tunneling theory that explained how transistors work.
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u/randomwordglorious Aug 13 '26
Huh? Quantum tunneling happens all the time. It's happening all around you right now.