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Baez talk at GR17

  1. Jul 2, 2004 #1


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    Besides the Hawking talk on BH information loss, and the public lecture by Roger Penrose on fadishness, wishful thinking, and fantasy in theoretical physics (or words to that effect) there is another interesting thing happening GR17

    Baez plenary talk on the state of things in
    Loop Quantum Gravity, Quantum Geometry, and Spin Foams

    It might get missed if I include it in the hawking GR17 thread, so i will make a separate thread for it.

    Here is the abstract from the GR17 program:

    --------quote from program-------

    John Baez (UC Riverside)

    - Loop Quantum Gravity, Quantum Geometry and Spin Foams

    The last few years have seen the techniques of loop quantum gravity applied to a growing number of problems. They have been used to compute the entropy of various sorts of black holes, including those with non-minimally coupled matter, for which the entropy is not proportional to the area. Perhaps more importantly, loop quantum gravity has given us a clear picture of the quantum geometry of the horizon, which accounts for the microscopic degrees of freedom responsible for black hole entropy. There are tantalizing connections to Hod's work on quasinormal modes, but these remain mysterious. Combined with traditional ideas on quantum cosmology, loop quantum gravity has led to new insights on how quantization can eliminate the singular behavior of geometry at the big bang - perhaps with testable consequences. Predictions of Lorentz symmetry violation may also be experimentally testable, but these remain controversial. Finally, the dynamics of the theory is being studied with the help of spin foam models. My talk will survey all this work with a bare minimum of technical details.

    ------end quote----

    the language "quantum geometry" has possibilities because
    Ambjorn has a book on simplicial gravity called "Quantum Geometry"
    published by Cambridge----that's his chosen name for the approach that includes his work with Loll using dynamical triangulations

    yet on the other hand "quantum geometry" is what Ashtekar calls what he does.

    and Ambjorn's simplex gravity is a close relative of spin foam.
    so Baez title is inclusive of several threads that seem on the point of joining
  2. jcsd
  3. Jul 2, 2004 #2


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    Here is the conference website, just to have the
    link handy

    http://www.dcu.ie/~nolanb/gr17.htm [Broken]

    that is where the summary of Baez plenary talk that I quoted comes from
    and it has lots of other good stuff

    these GR conferences (on all gravity matters) happen every 3 years
    and are something of a big deal
    Last edited by a moderator: May 1, 2017
  4. Jul 2, 2004 #3
    Thanks for all the information Marcus. :smile:

    Fads or no fads, the historical is truly revealling, as we move forward here with the information you have supplied.
  5. Jul 2, 2004 #4


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    sol it is so great to be on hand for this isnt it!

    the info is open and free
    and the merging of 1915 gen rel
    with 1925 heisenberg/schroedinger hilbertspace mechanics is
    happening in front of us
    it is a collision that will transform both of them
    and they are two of the greatest things humans did in the 20th century
    and maybe ever
    and when i turn on the computer it is a window to that

    wow wow wow
    Last edited: Jul 2, 2004
  6. Jul 2, 2004 #5


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    BTW sol I notice that you are as much a poet as a physics
    and i would say information-poet or
    science-collage poet
    or visionary science-collagist

    as much that as a physiker and maybe even more that than physiker

    so I am wondering if you like any rhyme-poets
    personally i think WmBlake is OK but I really really like
    the sound and meaning of Wm B. Yeats
    do you even know anything of yeats?

    the culture is dying of course so the younger you are the less apt to
    know any good stuff of yeats (what they anthologize of him is awful and i hate the lake Isle of Innesfree soooo much) you have to actually get his collected works and delve---but you may be too young
    a post-rhyme-and-meter generation
    Last edited: Jul 2, 2004
  7. Jul 2, 2004 #6


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    the trees are in their autumn beauty
    the woodland paths are dry
    under the October twilight, the water
    mirrors a still sky
    Upon the brimming water among the stones
    are nine and fifty swans.

    [frigging irishman knew how to write]

    the nineteenth autumn has come upon me
    since I first made my count;
    I saw before I had well finished
    all suddenly mount
    And scatter wheeling in great broken rings
    upon their clamorous wings

    [it goes on. it gets better and better]
  8. Jul 2, 2004 #7


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    that poem was written halfway between 1915 and 1925
    when the general theory of relativity (a geometric theory of gravity) had been spoken but when quantum mechanics was still like vague shadows on the dark water of the mind

    bohr had found a scheme in the colors of glowing hydrogen but there was still no quantum mechanics

    I have looked upon those brilliant creatures,
    and now my heart is sore
    All's changed since I, hearing at twilight,
    the first time on this shore,
    the bell-beat of their wings above my head,
    Trod with a lighter tread

    [I love that bell-beat so I made it bold]

    Unwearied still, lover by lover,
    they paddle in the cold,
    companionable streams or climb the air;
    Their hearts have not grown old;
    passion or conquest, wander where they will,
    attend upon them still.

    But now they drift on the still water,
    Mysterious, beautiful [ oh like the laws and constants of nature sol}
    Among what rushes will they build,
    By what lake's edge or pool
    Delight men's eyes when I awake some day
    To find they have flown away?

    [and that is the end, it has to be the end]

    [edit: companionable streams, I typed y instead of e]
    Last edited: Jul 2, 2004
  9. Jul 2, 2004 #8
    I wish I could respond directly, but what is amiss if one could not have respected all creative talent. To what orignates out of the minds of perspective generations of people? It might have been the anomalistic ( it is a play on the word and from Kuhn thinking :http://carbon.cudenver.edu/stc-link/bkrvs/kuhn/sixred.gif [Broken].

    Why the artist flare is not so far removed from the question of the science and the theoretcial journies?

    There is a rythmn in nature that just seems to make everything flow and once this perspective is recognzied from the source it originates, we are not so far remove from one another, that I too might not be called the mathematician :smile: I have a lot of Cognitives functions I speak about, that are truly not just my own? :smile:

    The creative inventors are truly numerous :smile:

    Ah now I see:

    A heart's passion and it's mate for life, would have been the true romantic views of one whose passion was science? :smile: Even in those Autumn years, Einstein's passion was not deluded, or the years unkind to the seeking.

    This unifying quest rests heavily on a lot of mind's hearts, and seeing two aspects of the issues of Solvay communitvely garnered around thought expeirments, indeed brings forth interesting perspectives. That has been very interesting for me to see this progression. It often reminds me today of the struggle between String's and LQG. Although your information is opening the doorway to a much larger perspective on these issues.

    I was fascinated to find Laughlin on the issues, Amidst the Matters for consideration, as well in Smolin's research. This through a interesting perspective for me about natures of the matters I had not understood before. I will try and find references for the future, for another thread.

    Alas, I am a poor sod( no collegiate standings) who find's enjoyment for the quest human nature has set ahead for themselves. :smile: Its often interesting the correspondance that arise in the mind when, one sees the jackets (I am thinking of http://sln.fi.edu/franklin/timeline/epitaph.html [Broken]) it can wear. "Reason" becomes a interesting topic.
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