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I Interesting controversy about inflation models of the universe

  1. May 11, 2017 #1
    I'm opening this thread for discussion on the latest debate over inflationary cosmology as outlined over at scientific american

    the original article on inflation was

    Scientific American published an article by Ijjas, Steinhardt and Loeb

    https://www.cfa.harvard.edu/~loeb/sciam3.pdf

    then a rebuttal signed by 33 physicists, A Cosmic Controversy,

    https://blogs.scientificamerican.com/observations/a-cosmic-controversy/

    followed up by a rebuttal again

    http://physics.princeton.edu/~cosmo/sciam/index.html#faq

    followed by a counter

    https://undark.org/2017/05/09/a-deb...d-editing-at-scientific-american-gets-heated/

    any thoughts comments

    any prospects of large hadron collider finding evidence of the inflaton ?
     
  2. jcsd
  3. May 11, 2017 #2
    Some people think the inflaton was found in 2012...
     
  4. May 11, 2017 #3
    I assume you are referring to the Higgs - higgs inflation model is not favored.
     
  5. May 12, 2017 #4

    fresh_42

    Staff: Mentor

    <moved and merged from another thread>

    I just found this interesting controversy about inflation models of the universe.
    As it is often a subject here, I thought, it might be interesting to our members.

    https://blogs.scientificamerican.com/observations/a-cosmic-controversy/
    This is a response on

    http://physics.princeton.edu/~cosmo/sciam/assets/pdfs/SciAm.pdf
    which led to the controversy.

    As a rare instance of scientific disputes to become public, I think it sheds some light on different views within the community of renowned cosmologists and how the emergence of opinions often evolves.
     
    Last edited: May 12, 2017
  6. May 12, 2017 #5
    What exactly causes Higgs inflation to be disfavored?
     
  7. May 12, 2017 #6

    kimbyd

    User Avatar
    Gold Member

  8. May 13, 2017 #7
    The most interesting thing in this is how Steinhardt once was one of the three kings of inflation/multiverse hypothesis and now he is the leader of criticism. It will be nice to see if anybody else will jump on his bandwagon. I hope so, because I think that eternal inflation specifically is BS.
     
  9. May 13, 2017 #8
    could our universe expansion due to dark energy be evidence of eternal inflation
     
  10. May 14, 2017 #9
    I am curious as to how Paul Steinhart squares his comments on inflation today with what we said when he brought his Ekpyrotic model when he said it was a myth that inflation makes no firm predictions
    http://wwwphy.princeton.edu/~steinh/dense8.pdf
     
  11. May 15, 2017 #10

    kimbyd

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    Gold Member

    No, not really. The magnitude of the expansion is vastly different. There have been a number of theorists who have considered that the inflaton and dark energy might potentially be the same thing (lookup "quintessence"), but so far nothing really compelling has come forward.
     
  12. May 15, 2017 #11
    ok.
    how about multiple bounces followed by a slow expansion The magnitude of the expansion is same as dark energy
     
  13. May 15, 2017 #12

    kimbyd

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    Gold Member

    During the rebound from the bounce, the rate of expansion would have been many orders of magnitude faster than the current expansion rate. I'm not aware of any models which connect the current expansion to the LQC bounce. I could certainly have missed those models, however.
     
  14. May 16, 2017 #13
  15. May 16, 2017 #14
    Are there any plausible models in which inflation is NOT eternal, and the multiverse is avoided?

    This seems one of the things that bothers Steinhart. I wonder if he feels the same way about MWI.
     
  16. May 16, 2017 #15
    There may be models of inflation that are not eternal but Planck data seems to favour models of inflation that are eternal according to Steinhardt.
     
  17. May 16, 2017 #16
    could we be in an eternally inflating universe with dark energy expansion as a part of it?
     
  18. May 17, 2017 #17

    I lost you here.

    Isn't Steinhardt saying that the Planck data experiments disfavour eternal inflation (and inflation all together)?
     
  19. May 17, 2017 #18
    That
    Thats not my understanding. in the paper they are very clear Planck favours models of inflation that are plateau like and these models are eternal. They then claim that there other conceptual problems with these plateau models.
    So the debate between these parties is no whether the Planck data favours multiverse models, it does. Rather the debate is whether the problems that arise in a multiverse such as the measure problem can be overcome or are they are so serious that an alternative like a cyclic model should be considered instead.
     
    Last edited: May 17, 2017
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