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Scientific American article about conference on Garrett Lisi's ideas.

  1. Aug 25, 2010 #1

    MTd2

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  2. jcsd
  3. Aug 25, 2010 #2

    marcus

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    Thanks for pointing to this news item by Zeeya Merali. Let's look at it and see if Merali can give us some new understanding.If so, I suspect that it is understanding in the history of physics department. Ultimately physics is the history of physics and understanding physics involves a kind of historical perspective, or so I think. Perhaps this short popular article can help us get perspective:

    == excerpt of SciAm item on the 2010 Banff ==
    ...
    ...

    In July mathematicians and physicists met at the Banff International Research Station in Alberta, Canada, to discuss a return to the golden age of particle physics. They were harking back to the 1960s, when physicist Murray Gell-Mann realized that elementary particles could be grouped according to their masses, charges and other properties, falling into patterns that matched complex symmetrical mathematical structures known as Lie (“lee”) groups. The power of this correspondence was cemented when Gell-Mann mapped known particles to the Lie group SU(3), exposing a vacant position indicating that a new particle, the soon to be discovered “Omega-minus,” must exist.

    During the next few decades, the strategy helped scientists to develop the Standard Model of particle physics, which uses a combination of three Lie groups to weave together all ...
    ...
    ...would only be a matter of time before physicists found an overarching Lie group that could house everything, including gravity. But such attempts came unstuck because they predicted phenomena not yet seen in nature, such as the decay of protons, says physicist Roberto Percacci of the International School for Advanced Studies in Trieste, Italy.

    The approach fell out of favor in the 1980s, as other candidate unification ideas, such as string theory, became more popular. But inspired by history, Percacci developed a model with Fabrizio Nesti of the University of Ferrara in Italy and presented it at the meeting. In the model, gravity is contained within a large Lie group, called SO(11,3), alongside electrons, quarks, neutrinos and their cousins, collectively known as fermions. Although the model cannot yet explain the behavior of photons or other force-carrying particles, Percacci believes it is an important first step.

    One fan of Percacci’s work is A. Garrett Lisi, an independent researcher with a Ph.D. in physics from the University of California, San Diego. Lisi hit the headlines in 2007 with his own attempt to embed a “theory of everything” in the most complex and elegant Lie group, called E8. Percacci’s work, Lisi says, “provides a nice unification of gravity and the Standard Model.”

    Lisi’s ideas revived mathematicians’ interest in this historical approach to physics, which led to the Banff meeting, says Gregg J. Zuckerman, an expert on E8 at Yale University. Lisi’s attempt, he adds, “represents a more general ideal about returning to Lie groups as a way to unify gravity with the Standard Model.”

    ... mathematician Tevian Dray and physicist Corinne Manogue ... are tearing them apart and examining ...an eight-dimensional number system called octonions. ... [neutrino chirality]
    ...neutrinos’ puzzling “left-handedness”—that is, their intrinsic quantum “spin” is always oriented in one sense relative to their motion.

    What is encouraging, [Dray] adds, is that many researchers are getting tantalizing hints, using differing approaches, that Lie groups are the right path to take. These hints are strong enough to stimulate mathematicians, such as Jeffrey Adams of the University of Maryland, to lend their expertise to physicists pursuing the Lie group approach. “I’d be disappointed if there’s not something like this that works,” Adams says.

    It is too early to judge whether the back-to-basics program will ultimately pay off, Zuckerman remarks...
    ==endquote==

    Of course it is "too early" :biggrin: This is the obligatory caveat which each science writer must always include. What makes it research is that it is too early to tell what to expect. But anyway there is our little Banff sketch of a present moment in the history of particles.
    I blued the names that Zeeya mentions because people are part of understanding history.

    http://www.scientificamerican.com/article.cfm?id=rummaging-for-a-final-theory&print=true
     
    Last edited: Aug 25, 2010
  4. Aug 25, 2010 #3

    marcus

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    What really got my attention about the 2010 Banff meeting was that Joe Wolf (whom I remember co-teaching with George MacKey one semester back circa 1970) said that Banff workshops are the North American equivalent of Oberwolfach. This may sound irrelevant to you or even silly :biggrin:. In any case that's simply how it is.
    Matilda Marcolli organized a 2010 Oberwolfach workshop on Spinfoams and Noncommutative Geometry. I see these two, Banff and Oberwolfach, as the premier unification meet-ups that have happened so far this year.
     
    Last edited: Aug 25, 2010
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