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Loop Quantum Gravity/Cosmology ~ for the layman?

  1. Jun 19, 2008 #1
    I've read Brian Greene's "Elegant Universe" and most of Lee Smolin's "The trouble with Physics". I found them both to be decent books. Honestly, I like them because they did not go to in depth with any math. I've read other misc papers that have been posted here at PF, but some of those equations make my head hurt. :shy: I really like how Greene explained the basics of string theory but, I haven't seen anything that was a LQG/C book/article for the layperson.

    Is there anything that is available? free or not..
  2. jcsd
  3. Jun 20, 2008 #2


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    No there isn't! It is a big gap. Someone needs to write that kind of nonmathematical book.

    You can always check at Abhay Ashtekar's personal website. He is currently the main leader in Loop Quantum Cosmology.
    At his website he has links to popularizations (illustrated magazine articles) and what he calls "semipopular" writing.

    some of the stuff at Ashtekar's website is about LQG (the full theory) and some is about LQC (the specialized application to cosmology, resolving the big bang into a big bounce).
    We should sift thru it. Some is likely to be several years old. I don't know of anything that is perfect.

    I just looked at Ashtekar's site
    and didn't see anything I especially liked in the "semipopular" articles list
    He is probably too busy to update the collection of links.
    Last edited: Jun 20, 2008
  4. Jun 20, 2008 #3
    So, what are you doing over the next 6 months..:rofl:
    But seriously, thanks for the link, I'll check it out. I also saw your thread with Singh's video.
    I guess I'll be starting there..
    Ok, I'm sure this is totally basic to you but, what is the difference between LQG & LQC. I'm assuming these are not about strings, but "loops" of some type? Working from that assumption, how does this make the big bang a bounce? Does that imply a "repeating or bouncing" universe of some sort? Is this the leading TOE candidate? .. sorry for my noobishness.
    Last edited: Jun 20, 2008
  5. Jun 20, 2008 #4


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    Loop Quantum Gravity is a potential theory of gravity, whereas Loop Quantum Cosmology is the cosmology coming from such a theory (in the same way that string/braneworld cosmology has its foundations in string theory).

    I'm moving this to Beyond the Standard Model, since it is better suited there.
  6. Jun 20, 2008 #5
    Thank you for clearing that up for me. So, is my assumption about "loops" as opposed to "strings" correct?
    Last edited: Jun 20, 2008
  7. Jun 20, 2008 #6


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    Actually there is a book that talks about LQG at a popular level: "Three Roads to Quantum Gravity" by Lee Smolin.
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