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No info transferred means SR and Entanglement do not conflict

  1. Mar 6, 2010 #1
    How is it that the lack of any info transferred between 2 entangled particles means that SR and Entanglement are not in conflict? I guess what I’m really asking is, well, it sounds to me like the lack of info is really just a lack of evidence that anything is transferred instantaneously. So if there’s no evidence that anything transfers instantaneously then you’re not breaking the locality rule of SR. So that leaves 2 choices. Either the 2 particles influence each other through some sublight path backward through time (which probably defies SR in some other way) or the influence occurs instantaneously, which does break locality and does defy SR.

    And even if the influence does occur instantaneously, who’s to say which particle was examined first? What I mean is that each particle is outside the lightcone of the other particle, right? So the decision of which particle was examined first really depends on your inertial frame of reference. I mean there’s always some inertial frame which sees the events occur in the opposite order from you. To say the corollary, if all inertial frames agree on the order of events, then one particle must be inside the other particle's lightcone.

    Aaaa! My noodle is so totally done cooking right now.
  2. jcsd
  3. Mar 6, 2010 #2


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    Well, first of all you need to remember that we in physics can only talk about things that we at least in principle can measure. The reason entanglement oes not violate SR is, well, because it doesn't...
    By that I mean that no one has ever been able to come up with a experiment where the predictions of QM and SR are in conflict when it comes to actual meausurement (as opposed to just interpretations).

    Also, you need to be careful when you talk about "particles" in this case, it is in my view not quite correct to talk about individual particles in this case; the mere fact that two particles are entangled automatically means that they are no longer distinct entities.
  4. Mar 6, 2010 #3
    OK, good point. So do you think it would be more accurate to say that even though all interpretations include a conflict with SR, there’s no way to demonstrate it? It seems a little misleading to me to flat out say that there is no conflict. Anyway, I think I’m treading a little too closely to interpretation here. And I don’t mean to. I am trying to stay agnostic.

    One question. I’d like to use the correct terminology so that I avoid any misinterpretation. So what language should I use instead of two particles when discussing entanglement of the Bell test?
  5. Mar 6, 2010 #4
    And thanks for such a quick reply.
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