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What makes virtual particles separate and come together?

  1. May 14, 2013 #1
    So virtual particles are supposed to pop into and out of existence because the uncertainty principle dictates a non-zero ground state of energy.

    My question is what causes the virtual particles to separate from each other, presumably with some velocity with respect to each other. And then once separated, what causes them to come back together? Is it because opposite charges attract? Or is there something more fundamental?
  2. jcsd
  3. May 14, 2013 #2
    Generally virtual particles they don't 'pop into and out of existence'....nobody has ever detected that actually happening....it's an introductory illustrative way to think about more complex mathematics. One way such imaginary events might happen is when gravity yanks particles apart at a horizon [see below].

    here is a better way to think about particle production....given a quantum field, say an idealized free electron not interacting...it's a field, you can't observe it....Now confine that field inside an event horizon, or capture that electron around a nucleus....it is confined when 'captured'...it resonates...it is finite in extent...it is a detectable particle!! Analogous to wiggly violin string: clamp the ends, tighten it perhaps, it now resonates at certain frequencies....

    and here is an even better description:

    I think I got this from Wikipedia....wherever, I like the description:

    On the other hand, even Stephen Hawking used a description of virtual particles separating at a black hole horizon to 'illustrate' Hawking radiation...although it had nothing to actually do with his mathematical calculations. The 'real; particle escapes to be observed.

    Also, it is worth noting quantum FIELDS, extended versions of particles, that expand in space with expanding space can become 'particles', which we describe as quanta [localized versions] of fields...what we detect. There are a variety of ideas about how this might happen.

    One way is via cosmological inflation: a dynamic spacetime geometry, like cosmolgicial inflation, can turn quantum fluctuations [ that we observe in the cosmic background radiation all around us] into particles at vast horizon scales. In other words, a changing, dynamic, spacetime geometry associated with event horizons produces real [observable] particles. Event horizons might be cosmological, black hole or Rindler type in Unruh radiation.

    edit: for more, search "virtual particles" in these forums...and

    Particle creation in an accelerating Universe?
    Last edited: May 14, 2013
  4. May 14, 2013 #3
    Yea, you caught me. That's exactly where I was heading. I was wondering if the Big Bang inflation could be responsible for separating virtual particles and making them real. I was wondering if the forces that caused virtual particles to separate in the first place might be what caused inflation. And once separated, could gravity be caused by particles wanting to rejoin to something? Thanks for antisipating my questions.
  5. May 14, 2013 #4
    virtual particle production due to inflation is Parker radiation, Hawking/Unruh is cosmological horizons
    Schwinger particle production is due to electromagnetic

    The Parker production as a cause of inflation was originally described as false vacuum by A.Guth however it is a form of Parker radiation.

    Here is a couple of related papers however I've never been able to find a good paper on Parker radiation specifically.



    Last edited: May 14, 2013
  6. May 14, 2013 #5
    Just found one written by Leonard Parker.


    an older one

    here is one on false vacuum its more recent than his original work, however he goes into a bit of inflationary model history in the article


    this one is his original paper

    Here is one on Hawking radiation in an FRW universe


    One on Unruh


    hope those help lol
    Last edited: May 14, 2013
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