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B Entangled particles and lorentz contraction?

  1. Apr 28, 2017 #1
    can lorentz contraction be measured via quantum entanglement with one of the entangled particles moving near the speed of light? would the particle in motion be affected by lorentz contraction? if so, would the particle at rest follow suit and appear affected?
  2. jcsd
  3. Apr 28, 2017 #2


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    Accelerating one entangled particle does not have a matching effect on the other, so NO.
  4. Apr 28, 2017 #3
    so entanglement has limited effect on its counterpart and isnt truely a "realtime copy" particle? are there other properties that dont follow suit in regards to entangled particles(such as mass increase as a result of the high speed)?

    to be clear i didnt mean the particle at rest would accelerate, but contract and distort like the particle in motion.

    i just understand entanglement as what happens to one particle, happens to the other via "spooky action at a distance".

    and if it doesnt "copy" over, is that the beginning of a way to monitor what happens near the speed of light without the "measuring device" being effected by time dialation?(the entanglement would have to maintain instantaneous communication even near light speed?)

    forgive me if im confusing or extremely ignorant, im new haha
  5. Apr 28, 2017 #4

    sorry i guess my true question is what happens when u have one of the entangled particles moving near the speed of light, if lorentz doesnt transfer, what else does and doesnt copy? mass, time dialation, ect. (velocity doesnt obviously) so does it nullify the effects of e=mC2,
    sorry one more question, if the lorentz effect isnt transferred, and assuming no properties of the kind are either, could we "watch" as one of the particles were thrown into a black hole, and how far could we possibly watch it go down the "hole"?
  6. Apr 28, 2017 #5


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    Entanglement does not operate as you envision it. As mentioned, accelerating one particle does nothing to the other. So naturally there is no relativistic effect to consider. No dilation, mass change, etc.

    Further, and in general: any operation done on one does nothing to the other unless it has the effect of acting as a measurement. When you measure one of a pair, the result is "as if" the other was measured in the same manner. No one can say precisely how that happens, there are varying interpretations of this mechanism.
  7. Apr 28, 2017 #6


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    No, since you don't get anything back from acting on the remote particle. There is no signalling going on.

    In fact: anything that might lead you to think there is "something" going from A to B falls victim to the point that it might instead be going from B to A. In other words: The order of events makes no apparent difference to the observed outcomes.
  8. Apr 28, 2017 #7
    so one could, in theory, toss one into a black hole and measure the other "as if"
    so, in theory, we have a way of measuring a particle fall into a black hole until the entanglement breaks. and better yet, we could, theoretically, toss that particle to the blackhole far faster than any classic devices(probe/satellite)..

    thank you for your time and helping me along the mind melting line of question!
  9. Apr 28, 2017 #8
    well now im confused again...if the remote particle cant be acted on even by the blackhole?
  10. Apr 28, 2017 #9


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    OK, a couple of more facets on entanglement and your black hole idea.

    1. The particle going into the black hole does not send any information back about it's interaction with the black hole.
    2. Observing a particle effectively breaks its entanglement with the other.
    3. The *most* you get from measuring your nearby entangled particle is information about the other particle BEFORE its interaction with the black hole.
    4. The results you observe from a series of measurements on entangled particles will be a random distribution. For example, spin measurements will be divided 50-50 regardless of axis.

    Note that the sequence of measurements is not important to the statistical results.
  11. Apr 28, 2017 #10


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    The remote particle can be acted on by the black hole, sure. It just does have any particular back reaction that could be observed on the local version.
  12. Apr 29, 2017 #11
    i think im following and i believe i recall a krauss lecture to that end. i appreciate the help and time very much, i clearly have to read far more into quantum mechanics before i can even pretend grasp it!
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