Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Loop quantum multiverse?

  1. Apr 27, 2013 #1
    Some time ago I was doing my dissertation on inflation and wrote to Martin Bojowald to ask if loop quantum cosmology was compatible with eternal inflation or not. He said at the time that no work had been done on the subject but it might be something to look at in the future.
    I have now found a paper entitled "Loop quantum multiverse?" he gave a seminar on it a few days ago, but it seems that paper went to the arxiv a few months ago:


    i think he is suggesting a multiverse might arise in a rather different way than is usually suggested in the eternal inflation scenario. Has anyone read this paper? Is this correct? Any thoughts?
  2. jcsd
  3. Apr 28, 2013 #2
    You are probably posting in the wrong forum. I was told here that "We strive to teach mainstream physics, not develop new ideas"

    Thank God all the greats, like Einstein and Newton didn't do this... (where is the sarcastic emoticon?)
  4. Apr 28, 2013 #3
    Actually I found the article fascinating. It does seem to suggest that the bounce mechanism can give rise to a multiverse scenario. My understanding of LQG is to poor to truly understand the details of the mechanism.
  5. Apr 28, 2013 #4


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    LQC is mainstream. Check this listing of quantum cosmology research since 2009
    It is ordered by number of cites, so the first 100 papers are the most-cited among the roughly 500 listed.
    The majority of these most-cited QC papers are LQC.

    Springer Press publishes a series of very mainstream handbooks they sell to university libraries. This year Springer will bring out one called the Handbook of Spacetime. The editor and some of the chapters' authors would be people you'd see in that listing of highly cited QC papers. Google "Springer handbook of spacetime" with the quotes---should get over 60 hits some of which will give an idea of the people asked to contribute chapters.

    One can't expect mainstream to be monolithic though. Not all the LQC folks would want to sign on to a paper like the one Bojowald just posted. That's no reason to say Bojowald is not mainstream however.
    Last edited: Apr 28, 2013
  6. Apr 29, 2013 #5
    First off i think this is the correct place to post the paper for discussion. Bojowald is a well respected theorist who publishes in mainstream journals (Nature, Physical review etc). I'm sure physics forums discourages wacky ideas from outsiders that seek to bypass scientific review. That's not the same as discouraging all new ideas.

    Marcus I know you are not a fan of the multiverse,so that Is why I would love your feedback on this paper. Always go to the biggest skeptic to review a new idea.
    As I understand the proposed mechanism here it is different to eternal inflation. What I think is that Bojowald is proposing is that when a universe collapses it doesn't just form one ultra dense region but several disconnected regions that then bounce. I think he is thus claiming a multiverse can form even if the eternal inflation mechanism turns out to be false. Have I understood this correctly?
    What problems do you see with this paper?
  7. Apr 29, 2013 #6
    That was the same conclusion I had reached on the mechanism. I don't necessarily buy any of the current multiverse theories. Including Chaotic eternal inflations bubble univeses. However I don't deny the possibility of a multi-verse. The problem I have with multi-verse theories is the mechanisms that are often used. However multiverse theories are popular among many of the biggest names in cosmology. So it would be easy to consider multiverse as a possibility to be a mainstay science.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Loop quantum multiverse?
  1. The multiverse (Replies: 19)

  2. Loop Quantum Gravity (Replies: 19)

  3. The Multiverse (Replies: 27)