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Before the Big Bang

  1. Apr 17, 2007 #1
  2. jcsd
  3. Apr 17, 2007 #2


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    It's my impression that the ekpyrotic idea was made up by Steinhardt and Turok quite a while ago, that interest in it peaked several years back and it has gone somewhat out of fashion.

    Could always make a comeback. :smile:

    Right now there aren't very many research papers being written about it.
    And in conferences about models that extend back before the big bang, they tend to ignore ekpyotic and focus on other stuff.

    You can check for yourself. There was a major 3-week workshop about this in January at KITP. KITP has some of the worlds top string thinkers and is directed by David Gross. The workshop was chaired by Gary Horowitz. (If you follow string those names are familiar to you.)

    but they did not appear to be much interested in ekpy. Not much in the way of talks scheduled. Not much discussion (compared with more recent ways of modeling back before big bang.)

    Check the schedule for yourself, to see what's currently 'hot'.

    Just google "KITP spacetime singularities"
    Or go directly to the program:
    most of the talks can be watched online video
    Last edited: Apr 17, 2007
  4. Apr 17, 2007 #3


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    Yeah, I found a link to the first "ekpyrotic" paper

    http://arxiv.org/hep-th/0103239 [Broken]
    Khoury, Ovrut, Steinhardt, and Turok

    as a rough indicator, since that paper appeared there have been 24 papers posted to arxiv that had "ekpyrotic" in the title
    and 14 of these were dated 2001 or 2002

    while 7 of them were dated 2003-2007

    that is the output of technical papers seems to have dwindled at least by this rough keyword indicator

    At the KITP workshop, "ekpyrotic" was mentioned but was dismissed for a technical reason. If you want I will try to dredge that up.
    But my main impression is just that since 2003 interest has declined among researchers, for whatever reason. (It could have to do with more general trends involving the whole string/M approach. It is hard to put one's finger on these shifts in research activity.)
    Last edited by a moderator: May 2, 2017
  5. Apr 20, 2007 #4

    Thanks for everything.I m just 1st yr undergraduate student of physics .I first saw at discovery channel about this theory.Is there any other theory that explain the cause of big bang.

    Specially i m crazy about string theory.As much i read about it i become more crazy.Now learning it through simple articles without maths.But i need learn maths.Can u advise me to prepare myself for string theory.Specaly need guidence about maths...
  6. Apr 22, 2007 #5


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    There are two ways to approach the issue of the origin of the universe.

    One is to postulate a classical regime beyond the big-bang that explains some of the features of the current universe, especially homogeneity and flatness. This approach is taken is Steinhardt's model, for example.

    In standard cosmology an inflationary phase is required after the big-bang in order to create homogeneity and flatness of space. The origins and initial conditions of this phase are unclear and require of new high energy physics.

    The idea beyond Steinhardt's model is that the contraction phase previous to the big-bang eliminates the need of an inflationary phase after the big-bang.

    The other approach is to take the kinematics of the inflationary phase as given and to analize the quantum behaviour of the universe near the big-bang. This is called quantum cosmology. Quantum cosmological models have to be able to explain the dynamics, origins and initial conditions of the inflationary phase.

    Quantum cosmological models require a theory of quantum gravity such as string theory. The surprising thing is that string quantum cosmological models predict a classical phase beyond the big-bang called "pre-big-bang". The basic feature of this models is a symmetry of the equations of motion that is called scale factor duality, that makes it possible to associate a contracting solution to every monotonically expanding solution.

    If you are interested in string cosmology the best place to find a list of papers is the home page of Maurizio Gasperini at http://www.ba.infn.it/~gasperin/. If you want to start with the mathematics of string theory I guess that the best way is to start with Barton Zwiebach's "A first course in String Theory".
    Last edited: Apr 22, 2007
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