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Quantum Vacuum and Quantum Foam

  1. May 9, 2014 #1
    How are the two related mathematically ie
    QV is SpaceTime devoid of matter and has Zero Point Energy on one hand
    QF on the other hand at PlanckScales SpaceTime fluctuates at high energies when probed

    Can you get Quantum Vacuum when probing Quantum Foam?
     
  2. jcsd
  3. May 10, 2014 #2

    Simon Bridge

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    The other way around.
     
  4. May 10, 2014 #3
    Ok Simon thanks, if QV is represented by ZPE lowest ground state, then how do you get the high energies at QV by probing it at QF scales
     
  5. May 10, 2014 #4

    Simon Bridge

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    The foam is virtual particles - look at the feynman diagram for a vacuum.
     
  6. May 10, 2014 #5
    Ok so we perceive Quantum Foam as Quantised SpaceTime at Planck Scales that spawns virtual particles hence explaining why we have additional energy over and above ZPE
     
  7. May 10, 2014 #6

    Simon Bridge

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    Not sure that "perceive" is a good term here.
    The "quantum vacuum" and "quantum foam" are different models designed to describe different effects.
    I don't think we have experiments that probe quantum foam effects. Well, not unambiguously.
    So the simple answer to your questions in post #1 becomes "nobody knows".
     
  8. May 11, 2014 #7
    Ok thanks, still would like to research this area, as I would like to understand the relationship or even an approach to the subject area, any good starting points would be appreciated

    Ie what physical process triggers virtual particles to appear out of a ZPE field

    I'm already aware of Casimir, but that is not at Quantum Vacuum
     
  9. May 11, 2014 #8

    Simon Bridge

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    It's spontaneous... happens by itself.
     
  10. May 11, 2014 #9
    Indeed, every action has a reaction
    If Spontaneity is the reaction what is inducing it ... Will dig further in to this ...

    Thoughts anybody is there a certain type of vacuum that is yet to be explored

    Given that we already have

    Classical Vacuum
    QED Vacuum
    QCD Vacuum
    LQG Vacuum
     
  11. May 11, 2014 #10

    Simon Bridge

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    There are some issues with your logic there:
    Even if every action has a reaction, not every reaction has an action. In QM it is fine to have effects without causes...

    Even if every reaction has an action, "spontineity" is not a reaction.

    Note: logic, by itself, cannot lead to synthetic truths. The truth of a synthetic statement cannot be known a-priori: you have to go look. When we look, things often turn out different.

    i.e.
    Action-reaction is Newtonian physics and only works on average.

    You have listed a bunch of different models.
    They are not different types of vacuum but different ways of talking about the one kind of vacuum in Nature.
    It's just maths. You can come up with any kind of model for a vacuum you like and then say, "This is an unexplored vacuum!" and you'd be right most of the time. There are infinite possible models for things. The trick is not so much coming up with models, they are easy, the trick is to come up with one that is useful.
     
    Last edited: May 11, 2014
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