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Vacuum Fluctuations

  1. Dec 9, 2014 #1
    I am interested specifically in the rate of formation of particle-antiparticle pairs in the empty void of vacuum space according to Quantum Theory? For example: for any given cubic centimeter of empty vacuum space, the rate of formation of electron-positrons is X pairs per second; the rate of formation of photons, or gravitons, is Y and Z pairs per second, and so on. The term "RATE" would include a complete cycle such as the creation-pairing-annihilation. How would these numbers be calculated according to QT?
     
  2. jcsd
  3. Dec 9, 2014 #2

    bhobba

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    The issue is complicated by the fact its now thought virtual particles are simply an artefact of the perturbation formalism used in QFT - they don't really exist.

    Its a bit hard to calculate what you are asking for things that are mathematical artefacts.

    Thanks
    Bill
     
  4. Dec 9, 2014 #3
     
  5. Dec 9, 2014 #4
    If they do not exist - then what explains Hawking Radiation or the Casamir Effect ???
     
  6. Dec 10, 2014 #5

    bhobba

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    We don't know at this stage because non-perturbative methods are still in their infancy. We simply know when they are not used virtual particles do not appear.

    Check out:
    http://www.mat.univie.ac.at/~neum/physfaq/topics/virtual

    'The collection of Feynman diagrams without loops describes exactly the scattering of classical fields in a perturbation theoretic treatment; the diagrams with k loops describe quantum corrections of order O(hbar^k). If virtual particles had a meaning, then they would already exist in classical field theory, since tree diagrams have internal lines. But nobody ever claimed that predictions of classical field theories bare caused by virtual particles.'

    Thanks
    Bill
     
  7. Dec 10, 2014 #6

    jtbell

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    As I understand it, there are ways of calculating both of these that do not involve virtual particles.
     
  8. Dec 10, 2014 #7

    bhobba

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    That's correct.

    Its just they are not as advanced as the pertubative methods and not understood as well since they are done on computer.

    Thanks
    Bill
     
  9. Dec 12, 2014 #8
    OK. Thank you for enlightening me about "virtual particles" - they don't exist. I would like to propose we end this discussion. I do have more questions that I will pose in some new threads. Thanks to all. Special thanks to Bhobba for the VP reference.
     
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