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I've read your article, and it helped me understand the shape of the proof, but I still don't understand it. If no information is transmitted between the peopl

I've read your article, and it helped me understand the shape of the proof, but I still don't understand it. If no information is transmitted between the people observing the quantum particles, how is it that you can improve their "performance" at the CHSH game above 75%? Like, what is the fundamental unit of "information"/coordination the players are extracting from their particles/qbits? Actually, while I'm being confused, what even is a qbit? From the descriptions, it sounds like it's not just an information, where two qbits with the same vector representation are equivalent, and it's more like a physical concept. Is it a particle? Or, like, it it some sort of global variable of the universe that stores some information that is undetermined until you "collapse" the global variable?

ahelwer 5y ago
A qbit is a mathematical model of some quantum phenomena that exhibits superposition & entanglement, like particle spin. The model seems to match the behavior rules of spin (and other quantum phenomena) as far as measurement and manipulation are concerned. Physicists generally avoid the question of whether nature really internally keeps track of the spin of a single particle with a complex 2-vector; instead we just say the model matches the experimental behavior as far as we have actually found, so the model is useful as a reasoning tool. Sorry for the sort of abstract answer. When we talk about information being communicated we're talking about someone choosing a bit that is then somehow reproduced with some fidelity somewhere else. Quantum entanglement doesn't allow such straightfoward possibilities. Instead it offers correlations that are stronger than would be possible with purely classical means. If this answer is frustrating because it doesn't match your intuition of what communication is - welcome to quantum mechanics! You just kind of have to learn the rules of the systems and get used to them. What you can do with entanglement (quite a lot!) is more important than what is "actually" happening under the hood.

ahelwer 5y ago

A qbit is a mathematical model of some quantum phenomena that exhibits superposition & entanglement, like particle spin. The model seems to match the behavior rules of spin (and other quantum phenomena) as far as measurement and manipulation are concerned. Physicists generally avoid the question of whether nature really internally keeps track of the spin of a single particle with a complex 2-vector; instead we just say the model matches the experimental behavior as far as we have actually found, so the model is useful as a reasoning tool. Sorry for the sort of abstract answer. When we talk about information being communicated we're talking about someone choosing a bit that is then somehow reproduced with some fidelity somewhere else. Quantum entanglement doesn't allow such straightfoward possibilities. Instead it offers correlations that are stronger than would be possible with purely classical means. If this answer is frustrating because it doesn't match your intuition of what communication is - welcome to quantum mechanics! You just kind of have to learn the rules of the systems and get used to them. What you can do with entanglement (quite a lot!) is more important than what is "actually" happening under the hood.