ELI5: Quantum entanglement
ELI5: Quantum entanglement
What is it, what are its consequences, how does it work, why is it there, why do we care about it?
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Okay, I am up for a challenge...
I am going to skip over all of the complicated Quantum Theory stuff and give you some general rules via a metaphor.
Let us say I have a box, in the box are two balls. Due to the laws of nature, the only way to be able to have two balls in this box is of one of them is red and the other is blue. If they are both red or both blue, they cannot go into the box.
Now, if I remove one of the balls without looking at it, carry it far away (as far away as you like...light years...other galaxies...etc) if you look at that ball and it is blue, the one you left behind has to be red because they were together in the box.
This cannot be used for instantaneous communication because you cannot influence which one is red or blue.
Part of the bizarre nature of this phenomenon is that the balls are neither red nor blue before one is observed. This is why it is called "spooky action at a distance". For the same reason Schrodinger's cat is both dead and alive in the box.
As for applications, it is debatable. Because the information is destroyed if observed at the wrong time (ie. wiretapped), there are discussions about using it to transmit encryption keys. Tests are ongoing.
I think this analogy is quite good :) something I've always been wondering though: In practice, how do scientists create entangled particles and separate them?
There are differenr methods but to name one, you have two particles very close to each other and then you bombard them with energy until they inevitably interact with each other and get entangled.