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I know I am missing something and this question is probably very silly, but I would like to understand. Quoting an article:

If one photon is measured to be in a +1 state, the other must be in a -1 state. Since the outcome of one photon affects the outcome of the other, the two are said to be entangled.......when you measure the state of one photon you immediately know the state of the other....If we’re light years apart, we each know the other’s outcome for entangled pairs of photons, but the outcome of each entangled pair is random (what with quantum uncertainty and all), and we can’t force our photon to have a particular outcome.

I just cannot see the "magic" here. Using a stupid analogy:
There are two balls, black and white, wrapped in a piece of cloth. You take one and I take the other. Whenever and wherever I unwrap the one I took, I will immediately know which one you have.

What is so special about that in the world of particles, how does the outcome of the first affect the other?

John V
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What is "magic" about entanglement is that entangled particles have a quantum state based on, or dependent on, the other particle(s) that it is entangled with. If you look at two random particles that aren't entangled, the quantum state of the first will tell you nothing of the second. However, if you look at first of an entangled pair, you will know the state of the second without ever observing it.

CuriousOne
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"There are two balls, black and white, wrapped in a piece of cloth. You take one and I take the other. Whenever and wherever I unwrap the one I took, I will immediately know which one you have."

How about this:

There are two balls, wrapped in cloth. You take one and I take the other. We repeat this every day. And this happens.

  • Whenever we both unwrap the balls with our left hands, we find that they have opposite colors.
  • Whenever we both unwrap our balls with opposite hands, we find that they usually --- but not quite always --- have opposite colors. (So maybe somehow using your right hand occasionally, but not often, changes the color of the ball somehow?)
  • Whenever we both unwrap our balls with our right hands, we find that they usually have the same color. (Now try to find an explanation for this that's consistent with the other observations.)

    • This, unlike the article you quoted, captures exactly what some people find mysterious about entanglement.

    WillO
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    The analogy you should consider is the case in which you and I both hold a coin. You toss your coin and I toss mine. Whether you get a heads or a tails I always get the opposite result. The results of our two supposedly random processes are perfectly correlated- that is the magic.

    Professor Sushing
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