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B Random transfer in entanglement

  1. Sep 22, 2016 #1
    It is said that entanglement doesn't violate relativity because there is no information transferred. Ther reasoning being Bob and Alice only get randomness even if there is correlation. But can random energy be transferred as it is still random? For example. Entropy decreasing at one place and increasing at another place in the entangled ends? What experiments have discounted (or proven) this?
     
  2. jcsd
  3. Sep 22, 2016 #2
    Or random energy transfer in the entangled ends. For example. Bob in Europa. Alice on earth. Alice will transfer heat to the Bob location in the moon Europa. Bob won't be able to get any information because Alice would send the heat random. Therefore can entanglement be used to teleport heat to another location?
     
  4. Sep 22, 2016 #3
    No.
     
  5. Sep 22, 2016 #4
    You are not sending information but random correlations.. please show an experiment that discounted that even sending random correlation is not allowed.
     
  6. Sep 22, 2016 #5

    bhobba

    Staff: Mentor

    Put a red slip in an envelope, green in another. Open one and you automatically know the other. Its just correlated and that is all the this Bell-EPR stuff is. It just has slightly different statistical properties. Nothing is transferred - you simply correlated the systems. If you insist QM is like the red and green slips that remain red and green at all times then Bell says something is transferred - but only if you insist its like that. Don't insist - no problem.

    Read Bells original paper where red and green slips have been replaced by Bertelmans socks:
    https://cds.cern.ch/record/142461/files/198009299.pdf

    Thanks
    Bill
     
  7. Sep 22, 2016 #6
    No. This answer should be worked out, theoretically, using QM formalism. Given QM is one of many theories used in science I would have thought proposing a new model of how the universe works would be needed to accommodate your thought experiment.
     
  8. Sep 22, 2016 #7
    They have setup where this can be disproven.. they showed that prior to measurement, the red and green slip doesn't even exist in the envelope. Something about Bell's Inequality equation that is violated. I'll take a look at it later and let you know when I found the reference.
     
  9. Sep 22, 2016 #8

    bhobba

    Staff: Mentor

    There is no experiment ever that has shown for red and green slips they did not exist prior to measurement - that would be classically absurd and slips of paper are classical objects.

    What Bell shows is if you want properties to exist prior to measurement then you need FTL. QM is silent on such things - but places restrictions. Bell and Kochen-Specker are the main ones.

    It would be wise if using experimental evidence to support a position to actually reference the experiment.

    Thanks
    Bill
     
  10. Sep 23, 2016 #9
    Yes, Bell and Kochen-Specker are the main ones. But earlier.. why did you that "Put a red slip in an envelope, green in another. Open one and you automatically know the other. Its just correlated and that is all the this Bell-EPR stuff is"? It's not Kochen-Specker but the old argument by Einstein handled already by Bohr nearly a century ago.
     
  11. Sep 23, 2016 #10

    Simon Phoenix

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    We don't really need to do an experiment to disprove this. The observed statistics at one end are unaffected by measurement at the other - so there is no experimental way to detect a 'decrease' of entropy at either end. As far as the endpoints are concerned there is nothing that can be measured at that endpoint that will tell whether an experiment at the other endpoint has been performed or not - it's only when we compare the results do we see the correlation.

    As Bhobba said - it's simply a pre-existing correlation - nothing is 'transferred' in the measurement process.
     
  12. Sep 23, 2016 #11

    bhobba

    Staff: Mentor

    Its a correlation like Bell. Simply another example of the Bertelmans socks type situation which is also a correlation. That's all EPR, Bell etc is. It just has statistical properties different to classical - but that changes nothing - you know one and hence the the other because they are correlated. No information etc passed. With one caveat - if you want it to be like Beterlmans socks or the slips of paper and have properties at all times then FTL communication is required - but only if that is what you want.

    If you want to discuss if energy is passed you need to reference a particular interpretation like BM. We have at least one expert here in it - but I am not one.

    Thanks
    Bill
     
  13. Sep 23, 2016 #12
    Ok. No information is passed because the spin up or spin down properties don't exist before measurement.. but can't we say the correlation is caused by information in the wave function that is omnipresent? There is still information involved that is holistic.

    You can numb it down by saying the wave function is not real and there is not even information that is involved.. but the simple fact there is correlation means there should be information involved.
     
  14. Sep 23, 2016 #13

    bhobba

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    I think you need to spell out the detail of EXACTLY what you mean.

    The correlation is usually a result of conservation principles.

    Thanks
    Bill
     
  15. Sep 23, 2016 #14
    Correlation in the Bell Aspect-like experiments can be changed or the setup influenced after the photons already left the emitter.. so the correlations involved is really something not classical (I think everyone knows this). Do you claim the Aspect correlation really classical and just some conservation principles? please elaborate your context.
     
  16. Sep 23, 2016 #15

    bhobba

    Staff: Mentor

    You seem to be jumping all over the place,

    I specifically claimed:
    If you don't get to the point you are trying to make then the mods will, correctly, shut this down.

    Thanks
    Bill
     
  17. Sep 23, 2016 #16
    It just has slightly different statistical properties... but there is correlation that can be adjusted instantaneous as per Aspect experiment. What I was describing is the standard belief. Maybe you also agree with me and we just have semantics mismatched. What is your point anyway (please get to the point)?
     
  18. Sep 23, 2016 #17

    bhobba

    Staff: Mentor

    I was explicit.

    This is my last comment. Its simply a correlation. No random energy is transferred.

    Thanks
    Bill
     
  19. Sep 23, 2016 #18
    Ok. I got your ideas anyways. I was thinking if there are ways for energy to be transferred.. but you said for the Bohmians.. energy may be passed. So let's give the floor to the Bohmians.
     
  20. Sep 23, 2016 #19

    Simon Phoenix

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    Yes, but I think that view depends on some assumption about the 'reality' of the wavefunction. It is the view to which I subscribe - but I also recognize the serious limitations with this perspective.

    If we work out the mutual information of the entangled state we find it's 2 bits. A classical 'Bertlmann's socks' type of correlation has a mutual information of 1 bit.

    The quantum state permits stronger correlations than a conventional classical counterpart of that state. I would view this by saying the quantum entangled state contains twice as much information in its correlation and see the things we can do with entanglement as a consequence of this extra information resource - but this 'ontic' perspective is not necessary.

    One thing we can say is that a hidden variable model has to access at least 2 bits of randomness if it is to reproduce the predictions of QM (we know this because spin-x and spin-z measurements at either end generate 2 bits of entropy and a hidden variable model has to reproduce ALL the predictions of QM not just the highly correlated ones) - so any hidden variable model based on a single binary random variable will not achieve its goal.

    We can attempt to view things in a holistic and ontic way by thinking of the collapse of some wavefunction caused by measurement at either end (and ignore the obvious relativistic problems) but there is no possibility of using this process to transmit information. In other words there can be no measureable consequence that will inform someone at one end whether an experiment has been done at the other. That includes no measureable consequence for 'energy' or 'entropy' - so to answer your question there's no transfer of anything physically measurable.
     
  21. Sep 23, 2016 #20

    Nugatory

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    We've supplied a number of "no" answers in this thread, and it is time to close it.

    As always, it can be reopened to allow further on-topic and helpful points to be made.
     
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