4 ms·
This is not how entanglement works, and while people do understand how entanglement works, it's a little subtle. When you measure your atom on earth, you will
by isaacg 4y ago
This is not how entanglement works, and while people do understand how entanglement works, it's a little subtle.
When you measure your atom on earth, you will get results with certain probabilities. When I measure my atom on the moon, I will get results with certain probabilities. My probabilities don't depend on how you performed your measurement - I can't tell what measurement you performed from just the results of my measurement.
However, our results will be correlated in unusual ways depending on our measurements. Maybe we both get a spin up result, or both get a spin down result.
These correlations go beyond the amount of correlation it's possible for classical objects to have, which is the essence of the Bell experiment, and specifically the CHSH inequality.
So entanglement can't be used to tell someone that the British are coming faster than normal classical communication. But it could be use to coordinate our responses (maybe both attack or both retreat, or one of each, with certain probabilities) in ways that can't be reproduced classically without using communication.
Hope that helps.
- anon1038471 4y agoIf I understand it correctly, two entangled qbits can can have their spin measured in the same order of planes (XY, YZ, XZ) to get the same result? So you can send a binary bit {0:no british, 1:british} or a qbit{XY:british probability, some other strategy dependent on XY spin and order of spin planes?}
- isaacg 4y agoNo, it is not possible to communicate any information by measuring one side of the quantum state. This is the no communication theorem: https://en.m.wikipedia.org/wiki/No-communication_theorem https://en.m.wikipedia.org/wiki/No-communication_theorem It's only possible to achieve correlations that are stronger than are classically possible without communication. Communication itself still cannot be achieved, by any sequence of measurements.
- TrapLord_Rhodo 4y agoTaken from your wiki link with a twist; "spooky correlation at a distance" does seem to be some amount of information. The paul revere joke was entirely out of scope, but the universe does seem to have some way to pull the strings behind the curtain here.
- kgwgk 4y ago> does seem to be some amount of information How so? How would you define information and its communication?
- zaphar 4y agoI don't have the background to really understand this but it sounds like: in order for information (we correlated our spins) to be passed you would first have to know what the other side is doing which requires side band communication which itself would be subject to the speed of light. But I might be missing something in my understanding.
- isaacg 4y agoThere is something to that - there's a concept called "Quantum Nonlocality", which says that an accurate description of an entangled quantum system must be nonlocal - to predict what will happen, we need to look at the whole system at once. But nonlocality is different from the capacity for communication. To make accurate predictions about the measurements, one would need information from the earth and from mars. However, the results of the measurements cannot be used to transmit information. These two concepts - what is necessary for prediction and what the results can accomplish - often line up in the classical world, but in the quantum world they are quite distinct. So your intuition has merit, but it reveals quantum nonlocality, not quantum superluminal communication.
- Anunayj 4y agoOh wow! This clears up the whole quantum entanglement thing for me, which I never understood, nor looked into it. So it's like syncing up the state of of two PRNGs!