Please explain to me quantum entanglement.. and can we “ hypothetically “ build a quantum entangled cameras or some sort of optical device one we can observe on and them put this device in a space shuttle or smt then we can observe events in time ?
Let’s just say this device is 1 light years away but it’s entangled with a device here on earth so events will reach us 1 in 1 year or just in time?
In: Physics
You get entangled particles typically when they are created in one event. The most basic example is spin, you have a particle with 0 spin and it decays into two particles with both spin 1. Now you know that whatever direction you look one particle must be spin +1 (up) and the other has to be -1 (down) because angular momentum is conserved.
We know that there are no local hidden variables which would be equivalent to the particles picking down or up at the moment of their creation, for a given axis they are in a superposition lets say 50% up + 50% down, but angular momentum is conserved. How do we know that they didn’t pick in advance? If you were to measure one particle along a different axis you wouldn’t get 50-50 +/- 1 in that direction you’d get some slight skew towards one which is not what QM tells us and experimentally the prediction that QM makes is the valid one.
So we can say that when I measure particle A it goes into the spin up state and immediately particle B enters the spin down state regardless of their distance. This may at first give the wrong impression that you can send information faster than light (FTL) through this process but no you can’t. For one you didn’t get any information FTL because all information was available locally to figure out the spin of particle B. You know they were created from one event and so you know they have to be entangled to make sure angular momentum is conserved and you measured the spin of particle A. The whole system (this two particle system) contains these two pieces of information. You also didn’t send information because a quantum system doesn’t hold information about its “measurement status”, meaning you cannot preform any experience on B to show that its “wavefunction has already collapsed”.
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