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I Can Dark Matter just be vacuum fluctuations?

  1. Mar 24, 2016 #1
    Has there been any theories proposed that model Dark Matter as just the pressure from vacuum fluctuations? It would be just a big cosmological-scale version of the Casimir Effect, where instead of using a couple of plates separated by microns, we're using the gravity wells of galaxies to create low-pressure regions of space, separated across thousands or millions of light-years.
     
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  3. Mar 24, 2016 #2

    mfb

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    Quantum field theory allows to estimate an energy density of those quantum fluctuations - but that estimate is a factor 10120 too high. It is an open question if
    (a) that calculation makes sense at all,
    (b) there is some particular reason why our estimate is way off, or
    (c) we do not understand the problem.

    Either way, dark energy is not just a casimir-like effect, because that is absolutely negligible on cosmological distances.
     
  4. Mar 24, 2016 #3

    wolram

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    Are we talking dark matter or dark energy here?
     
  5. Mar 24, 2016 #4

    mfb

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    Oh, good point. The QFT vacuum doesn't have any connection to dark matter so I read "dark energy" somehow.
     
  6. Mar 24, 2016 #5

    PeterDonis

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    No, because that pressure behaves the wrong way to account for dark matter. The pressure due to vacuum fluctuations causes repulsive gravity--it behaves like dark energy. But whatever it is that dark matter turns out to be, it must have attractive gravity, like ordinary matter, because it's the presence of "extra" attractive gravity--i.e., more of it than can be accounted for by the matter we can see--that signals the presence of dark matter.
     
  7. Mar 25, 2016 #6
    Not necessarily, if our calculated matter continues to = ordinary matter * 2 Pi (+/-3%) we may just be missing a translation factor of 2 Pi somewhere. If this turned out to be the case a simple correction would lead to much less dark matter along with minimal attractive gravity.

    It's interesting to note that basic equations when solved for m, that contain the reduced Compton wavelength XOR the reduced Planck constant have an implicit 2 Pi present in their most basic forms UNLESS the equation includes phase velocity then things will be reversed and 2 Pi becomes implicit in the other equation forms where (standard Compton wavelength AND standard Planck constant) OR (reduced Compton wavelength AND reduced Planck constant) appear. So, coming around full circle, equations that contain the reduced Compton wavelength XOR the reduced Planck constant will NOT have an implicit 2Pi present in their basic forms if they are solved for m and phase velocity is present.
     
  8. Mar 25, 2016 #7

    mfb

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    No, that does not work. We know the gravitational attraction between regular matter very well - we can measure it in a lab. The gravitational constant is measured in that way. There is no additional factor around.
    That does not make sense, but it is completely irrelevant anyway - the mismatch of matter and gravitational forces is purely based on classical mechanics.
     
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