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Lightspeed and entanglement 'phone' question

  1. Oct 16, 2012 #1

    I'm new to the forum and registered as I have a scenario which has me confused (not difficult!)

    The scenario goes as follows and involves:(and please correct me if anything I'm suggesting is incorrect)

    -person A journeys to a nearby star and travels near the speed of light

    -person B remains on earth

    -a 'space phone' based on a quantum entanglement communication device.

    So, person B says goodbye to Person A and shoots off on his trip to a nearby system. As he travels at nearly the speed of light the round trip to him will take say 40 years, however when he returns to earth person B has experienced 70 years. During the trip person A has experienced time differently to person B.

    My (super basic) understanding of quantum entanglement is that the state of one half of an entangled pair changes instantaneously when the other halves state is changed, irrespective of distance. So if a phone call where to take place on the 'space phone' each half of the entangled pair would be experiencing time differently but also have to change states simultaneously...?

    How/Could this work, is it even possible or what would the phone call sound like!?

    I'd be really interested to hear any insights into this, many thanks.

  2. jcsd
  3. Oct 16, 2012 #2


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    Science Advisor
    Gold Member

    Quantum entanglement can NOT be used to make a faster-than-ligh communication device, so the problem never arises.

    This is a very common question, but it is based on a missunderstanding when it comes to what quantum entanglement is.
  4. Oct 16, 2012 #3
    I see, thanks for the reply. So is there any good, basic, reading that would give a better understanding quantum entanglement, what it is and how it works?
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