Can someone explain the 2022 nobel physics winner’s experiments and what they prove more simply?
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Quantum mechanics is a well established theory, but predicts many weird effects. One of these is that particles can become “entangled”which means that they share some properties. Then these particles can move apart, but the entanglement is retained. If we measure the property of one we will know instantly the property of the other. So far so simple, but the key thing is that the particles don’t have the property in common, and we just look at it. They exist in a superposition, meaning it could go either way. Then the act of measurement “collapses the wavefunction” meaning that the measured particle randomly “chooses” which option it has. That information is then passed instantly to the other particle, violating our understanding of how information can only travel at the speed of light.
One way to avoid this contradiction is to invoke “hidden local variables”. Basically we say that maybe the two particles do actually agree on which way they will go ahead of time, and that information is stored in the hidden variables. This is great at avoiding the contradiction (preserving “local realism”), but isn’t actually predicted by the scientific theory.
Someone called John Stewart Bell pointed out that under certain conditions a pair of entangled particles would behave differently under standard quantum mechanics vs if hidden variables are real. This allows an experiment to be set up to test which theory is actually real.
One of the winners, Clauser, was the first to do such an experiment, but the setup had flaws called “loopholes”. Another winner, Aspect, closed some of them. It has taken 50 years to be confident we have closed all the loopholes and that local hidden variables don’t exist.
So the result is to confirm that this aspect of quantum mechanics really is as weird as it seems, that entangled particles really do “communicate” faster than the speed of light. The way that the experiments were set up varies widely, so it’s a bit hard to explain all of them. Basically you measure a bunch of entangled particles and see how the random distribution turns out.
Those experiments prove that the randomness of quantum mechanics occurs not because we don’t know something, and if we knew that we could predict the outcome of every single experiment precisely. Instead, some things are truly random, so such a degree that randomness can travel faster than light in order not to violate quantum mechanics.
Please see the previous thread (and remember to use the search bar in future):
ELI5 what “the universe is not locally real” means.
byu/Udontwan2know inexplainlikeimfive
Im glad you asked this because i actually just spent the last few days binging explanations and I think I understand now how to properly explain it simply.
Imagine you make a wishlist of presents you’d like to recieve for christmas. Lets say, your wishlist has on it 2 items “xbox, ps5”. So on chrismas santa drops by your house and you receive two wrapped gifts. Presumably ones a ps5 and the other is an xbox, but the box is wrapped up so you dont know which is which. lets say you open the box on the left and its a ps5, therefore u immidiately know the box on the right is an xbox. Now answer the following question: “was the box on the left a ps5 before you openned it?”. You’re an adult so you say “duh ofcourse”.
But if you were literally 5 years old, you might be too young to understand [object permanance](https://en.wikipedia.org/wiki/Object_permanence). When we are young we are literally too stupid to understand that things still exist even when you cant see them. When you pay peek-a-boo with a baby and you cover your face, the baby is genuinely confused and wondering where you disappeared off to. If it was a 5 year old in the aforementioned gift scenario, he might genuinely believe that when he opens the box the gift inside decidedly becomes a ps5 at the moment of opening. kids are dumb. So lets ask this kid some more questions, to see how ridiculous his answers are.
“if the contents of the box *became* a ps5 at the moment of opening, then what was inside before you openned it?”
-“uhhhhhh, it was a ps5 and an xbox”
“at the same time?”
-“ahh yeahhhh”
“okkay….and what about the box on the right? whats inside of that?”
-“an xbox”
“ahh so you’re smart enough to understand basic logical deduction! cool, and did the box on the right always contain an xbox? or did the contents become an xbox suddenly when you opened the box on the left.”
-“uhmm, it became it once i opened the ps5’s box”
“instantly?”
-“yes”
“but how did the box on the right know when to become an xbox, it would have to receive a signal from the box on the left telling it ‘i turned out to be a ps5 so you should become an xbox.’ nothing in the universe travels faster than light, so it couldnt be instant.”
-“yes it is, its instant”
Imagine this child grows up never understanding object permanence. He would think that everything in the universe is in an indefinite state of multiple possibilities until he looks at it. He thinks that once he finally looks, then and only then is one of the possibilities randomly chosen and definitively becomes reality.
This viewpoint is perposterous and deserves scrutiny. What counts as “looking?”. “Why is it probabilistic?” “Why is influence able to travel faster than the speed of light, but nothing else in the universe is?”
But is there any way to prove him wrong? Can you try thinking of designing an experiment that scientifically debunks him? Kinda hard right? Its like trying to come up with an experiment to prove god is real. It seems untestable. This sounds more like a philosophy riddle than a scientifically testable theory. Kind of like “if a tree falls in the forest and there’s no one there to hear it, does it make a sound”
The winner of the 2022 nobel prize figured out just that. They designed an experiment to test this idea. The result was shocking. They proved that the kid may have been right all along.
This post is getting long so i will explain the experiment in a reply to this comment.
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