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So recently I watched a MinutePhysics explanation of quantum teleportation. Recently I have also been asking questions about quantum entanglement, and the answer I am most often getting is faster than light communication is not possible.

In the video by MinutePhysics, he talks about how by having two entangled particles then entangling the thing you want to teleport with one of the entangled particles you can teleport the thing’s state to the second entangled particle.

To me this sounds like communicating the thing you want to teleport’s state faster than the speed of light. Is it though?

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    $\begingroup$ en.wikipedia.org/wiki/Quantum_teleportation says "faster than the speed of light" three times. Always in the context of explaining why that doesn't happen here. $\endgroup$
    – Connor Behan
    Commented Jan 16, 2023 at 0:40
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    $\begingroup$ Indeed, "Because of this need for the traditional channel, the speed of teleportation can be no faster than the speed of light ... " is the third instance of the phrase on the page, so maybe read at least the preceding paragraph. $\endgroup$
    – march
    Commented Jan 16, 2023 at 4:29
  • $\begingroup$ Exactly what information do you think is being communicated? $\endgroup$
    – WillO
    Commented Jan 16, 2023 at 7:13
  • $\begingroup$ physics.stackexchange.com/a/282869/28512 $\endgroup$
    – alanf
    Commented Jan 16, 2023 at 11:36

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The reason is because it is not actually "communicating" any new information at all.

Think about it. If I flipped a coin and it came up "heads" would you say, "Ah! What an interesting message!" No, because that is an expected outcome that doesn't give any new information.

The "spooky action at a distance" of entanglement is not useful for communication, because without comparing the results of both sides (at standard light-speed and lower rates) the outcome is meaningless.

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