Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I Quantum nonlocality in relation to FTL Communication

  1. Aug 31, 2016 #1
    With a modest understanding of 'spooky action at a distance', I've been informed that using entangled particles as a form of quantum bit system would not work for vast distances. It wouldn't be a viable option to communicate instantly with points like our moon, satellites orbiting Jupiter, or interstellar distances.

    Hypothetically if one could create two quantum computers, each with the other half of an entangled set of particles (that could be accurately measured), you could leave one on Earth and send the other off to deep space. Any quantum bit information would be spontaneously emulate in both directions.

    Was hoping someone could share what I'm overlooking.
    http://static1.techinsider.io/image/562a8cb0bd86ef16008c4635-1097-470/screen%20shot%202015-10-23%20at%203.36.58%20pm.png [Broken]
    Last edited by a moderator: May 8, 2017
  2. jcsd
  3. Aug 31, 2016 #2
    You can't use entangled particles for any kind of FTL communication anyway.
  4. Aug 31, 2016 #3

    Vanadium 50

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2017 Award

    If you wrote down something on two pieces of paper and sent them far away, isn't that the same thing?
  5. Aug 31, 2016 #4
    The correlation between the values of the two particles can't be observered locally; one has to bring together the outcomes of the two measurements, and that can't be done faster than light. Locally (at one particle of the pair) one observes randomness.
  6. Aug 31, 2016 #5


    User Avatar
    Science Advisor
    Gold Member

    Just to say the same thing as the above answers but with different words: the bit you are discussing will have a random value. Not a lot to be gained from looking at random bits of information.

    I.e. you cannot "force" an entangled particle to take on a specific value.
  7. Aug 31, 2016 #6
    Thank you. That answer was clear. So one limitation is the inability to manipulate particles into specific values.

    My understanding is that the original concept would overcome FTL communication because there is no information "traveling". They are two particles that intrinsically behave as opposites. Probably should have avoided the FTL reference.
  8. Aug 31, 2016 #7
    Wouldn't be the same thing if you could manipulate what you wrote on the paper at either end. Change what is written on one page and have it intrinsically reflected in the other. But from 'DrChinese' response it is that very manipulation that would be a stumbling block.
  9. Aug 31, 2016 #8
    If measured, the systems are no longer entangled. So doing a further measurement (or manipulate) one of the systems won't cause the other system to react to the further activity conducted.
  10. Aug 31, 2016 #9
    Ah! That's helpful too.
    Thanks Stevie.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted