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To stir the pot Post inflationary period

  1. May 2, 2013 #1
    My question is what sort of material/matter existed to allow an expansion of the early universe?

    It had to be some sort of vacum state...and it had to be lower/negative values outside of the expansion?
  2. jcsd
  3. May 3, 2013 #2


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    Nope. Ordinary radiation and non-relativistic matter lead to an expanding universe.

    There was no "outside the expansion". You might want to familiarize yourself with how to understand the expanding universe: the balloon analogy might help: http://www.phinds.com/balloonanalogy/
  4. May 3, 2013 #3
    To expand on this,

    All models that describe a possible mechanism that caused the inflationary era (specifically) are from effects within our own universe. The original inflationary mechanism commonly called false vacuum by A.Guth involves a false vacuum to a true vacuum with virtual particle production. Many later models use a similar methodology. False vacuum is your minimal vacuum state, true vacuum the state its now in. Google false vacuum for more detail.
  5. May 4, 2013 #4
    Thanks for the info, from both members. I will look into both links.

    That's a killer line regarding the deodorant...

  6. May 4, 2013 #5
    Lol yeah I laughed my head off the first time I saw that line.

    The false vacuum model is niw commonly referrred to as old inflation. It had several problems pointed out by Guth himself. You have to give him credit its rare to see the inventor of a model point out its own problems.
    The probkem he pointed out is called runaway inflation. There was no mechanism to stop it. Later models provided a vareity of mechanisms. So I will pointed out a few key ones.
    Although in some of the good fit models they take adviantage of the runaway.

    Slow roll inflation.
    Chaotic inflation
    chaotic eternal inflation
    natural inflation
    hill inflation.

    The above is a short list compared to the number of models. However they are all considered good fits to observationsal evidence.

    The slow roll approximation is often used a a comparision model. So its of particular interest.
    Other historical inflation problems include the following.

    Flatness problem
    horizon problem
    monopole problem

    Later inflationary models provide solutions to these problems. I mention them as you will encounter them in your studies
  7. May 4, 2013 #6
    Forgot to mention you will come across the term inflaton field. Some models use this. Sone however don't. The Higgs field is also in some models such as false vacuum and later models.
    I have a technical review paper if your interested but its pretty advanced.
  8. May 4, 2013 #7


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    All successful inflation models -- not just later ones -- should provide solutions to these problems (it's what makes them successful). As you mention, Guth's original "old inflation" is perhaps the one exception -- it failed to solve them due the failure of nucleated bubbles of true vacuum to coalesce efficiently and delicately enough. But other "older" models are successful, like Linde's "new" inflation and chaotic polynomial inflation.
  9. May 4, 2013 #8
    I've sort of had a grasp on the balloon model, some one told me think of painting dark spots on a half inflated balloon and watch the spots increase distance from one another as you inflate the balloon more.

    I like any simple sort of analogy along those lines....
  10. May 4, 2013 #9
    Thank you again, I will look into these as well...
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