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B Free fall of atoms

  1. Jul 19, 2016 #1


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    Staff: Mentor

    I have found an article about an experiment that states that gravity on a small scale doesn't experience quantum effects. Of course the headline has been catchy, so I want to ask about the real importance or relevance of the experiment.

    Or for short: Do the results imply any consequences on GUT's.

  2. jcsd
  3. Jul 21, 2016 #2


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    That is a misleading description.

    The experiment shows that the spin of rubidium atoms does not influence the gravitational acceleration (within the experimental uncertainty, as always). It would have been really weird if it would.

    Gravitational fields quantize energy states of particles, this has been demonstrated with neutrons. The gravitational field has the same role as electrostatic fields for experiments with electrons or protons.
    Here is an example
  4. Jul 21, 2016 #3


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    As far as I know, gravity has only been experimentally tested against predictions of GR at scales as small as about 10^-6 meters (about 1,000 million atomic radii long), where one might expect classical behavior, even if quantum gravity effects are real, because this is far larger than the atomic scale of around 10^-15 meters.
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