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Quark-gluon plasma

  1. Sep 26, 2012 #1
    Quark-gluon "plasma"

    I understand that recently an estimated temperature of 5.5 trillion K was achieved at CERN. The phase state is described as a frictionless liquid. Is it still a plasma since the term continues to be used?

    Also, up to what temperature is QCD considered valid?

    http://blogs.nature.com/news/2012/0...ts-create-record-breaking-subatomic-soup.html

    EDIT: It seems QCD breaks down at 2 trillion K. Are there any quantum theories that are valid for quark-gluon plasmas if in fact they are true plasmas?.
     
    Last edited: Sep 26, 2012
  2. jcsd
  3. Sep 26, 2012 #2
    Re: Quark-gluon "plasma"

    Yes, it's definitely a plasma.

    QCD is valid at all temperatures, as far as I know. You can unify the strong interaction with the eletromagnetic and weak forces at high enough energies, but QCD should still be "valid"
     
  4. Sep 26, 2012 #3
    Re: Quark-gluon "plasma"

    OK. Thanks for the response. But I added an edit to my first post because of this:

    http://physicsworld.com/cws/article/news/2011/jun/23/quarks-break-free-at-two-trillion-degrees

    I guess Lattice QCD is still QCD.
     
    Last edited: Sep 26, 2012
  5. Sep 26, 2012 #4
    Re: Quark-gluon "plasma"

    It isn't really frictionless, I think. Close enough for jazz though
     
  6. Sep 27, 2012 #5
    Re: Quark-gluon "plasma"

    Yes.Lattice is a numerical algorithm of QCD.
     
  7. Sep 27, 2012 #6

    tom.stoer

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    Re: Quark-gluon "plasma"

    Lattice QCD is a rigorous reformulation of the QCD equations tuned for lattice calculations and Monte Carlo simulations. It is an approach that allowes us for non-perturbative calculations, i.e. investigation of regimes where bound states dominate and where the coupling is large.

    From a QCD perspective QCD remains valid at all energies, but there are other forces which will become stronger at higher energies and which may be unified with QCD; but this is outside the QCD scope.
     
  8. Sep 27, 2012 #7
    Re: Quark-gluon "plasma"

    I'm familiar with the Monte Carlo method. For example, in Monte Carlo integration one has an intractable integral: [itex] I = \int_a^{b} f(x) dx [/itex] which is approximated by:

    [itex] \hat I = \frac{b-a}{n} \sum_{i=1}^{n} f(x_{i}) [/itex] where [itex] x_i [/itex] are independent observations from a uniform distribution on the interval (a,b).

    I'll try to figure out exactly what a, b, and n are in this context on my own and leave the functions undefined. I'll come back if I get stuck. Thanks
     
    Last edited: Sep 27, 2012
  9. Sep 27, 2012 #8

    tom.stoer

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    Re: Quark-gluon "plasma"

    In lattice QCD the integral to be evaluated is a so-called path integral
     
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