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Observable QG effects in Chern-Simons gravity-Stephon Alexander

  1. Nov 27, 2009 #1

    marcus

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    Observable QG effects in Chern-Simons gravity--Stephon Alexander

    Important talk,
    http://pirsa.org/09110132/
     
  2. jcsd
  3. Nov 27, 2009 #2

    atyy

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    Re: Observable QG effects in Chern-Simons gravity--Stephon Alexander

    Cool. Danke!
     
  4. Nov 28, 2009 #3

    marcus

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    Re: Observable QG effects in Chern-Simons gravity--Stephon Alexander

    Bitte! It's an impressive talk. In fact Planck mission will collect polarization data on the microwave background and will provide finer resolution. He mentioned that Planck team will be looking for effects that the CS variant of gravity predicts. He mentioned talking to Clifford Will and David Spergel about it and that they were excited.
     
  5. Nov 28, 2009 #4

    marcus

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    Re: Observable QG effects in Chern-Simons gravity--Stephon Alexander

    Another talk by Stephon:
    http://pirsa.org/09110138/

    He presents a brilliant high-risk model that proposes that dark energy is a condensate
    and if correct would explain both dark energy and neutrino oscillations.

    In the audience, questioning and commenting, are Michael Peskin (current visitor at Perimeter), Lee Smolin, Laurent Freidel, the PI director Neil Hurok. The most persistent and grilling was by Michael Peskin.

    Stephon has a paper on this idea which has been submitted at arxiv and which he expects will appear on Monday 30 November.
    For me, because of the time difference, that means tomorrow at 5 PM pacific time.

    He also mentioned that there is another group working on related ideas and that he got "scooped" last week re some minor result. I don't know who the other authors are.

    Stephon is in a strategic area---at a confluence. He does phenomenological cosmology---on the border where observation of the cosmos meets general relativity and particle physics. He works with particle fields put in a general relativity Lagrangian. His viewpoint is agnostic about the various approaches to Quantum Gravity--but requires that what he works on have observable effects---that's the phenomenologist's angle.

    Interesting guy,born in Trinidad (around 1971?) raised in Bronx, heavy Bronx accent. BS Haverford 1993, PhD Brown 2000, Princeton, London Imperial, SLAC-Stanford, and now faculty appointments at Penn State (Ashtekar's Institute) and Haverford.
     
    Last edited: Nov 28, 2009
  6. Nov 29, 2009 #5

    atyy

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    Re: Observable QG effects in Chern-Simons gravity--Stephon Alexander

    H2N2? I can't tell if he's kidding.
     
  7. Nov 29, 2009 #6

    marcus

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    Re: Observable QG effects in Chern-Simons gravity--Stephon Alexander

    I just thought he meant H1N1 (a strain of flu that is going around).
    I've seen it on the web being misprinted as H2N2 by an odd computer error, where some material is optically scanned and the optical character recognition sees a "1" in a large-serif font and interprets it as a "2". So there has been some confusion.
    Could be just a memory glitch on the speaker's part. Unless I'm mistaken, the real H2N2 goes back to a serious outbreak in 1957. The only person I can imagine actually having a case of it would be a negligent lab tech or a volunteer participant in some experiment (wouldn't like to think about either.)
    ==========================

    Today this came out on arxiv:
    http://arxiv.org/abs/0911.5156
    A Theory of Neutrino Oscillations and Late Time Acceleration
    Stephon H.S. Alexander
    6 Pages, 1 figure
    (Submitted on 26 Nov 2009)
    "We provide a microphysical model that connects neutrino oscillations to dark energy, which has predictions of Lorentz and CPT violating neutrino oscillations. We argue that the DE is a BCS condensate of flavored neutrinos. As neutrinos propigate in their own condensate they naturally have oscillations proportional to the DE energy density. All that is assumed in this model is a covariant coupling of neutrinos to gravity and a finite number density of neutrinos in the cosmic rest frame; this situation yields an attractive channel for the formation of a spin zero neutrino condensate leading to late time acceleration self consistently. Moreover, the vacuum oscillation has two predictions: (1) CPT violating oscillations proportional to the DE density (2) A connection between the evolution of the equation of state of the DE condensate and the neutrino oscillations. These predictions can be probed independently with future Supernovae and Neutrino Telescopes."

    And also this came out: which suggests that somebody might have scooped somebody, or come very close to it.
    Stephon mentioned in the Perimeter talk that he thought he might have been scooped.

    http://arxiv.org/abs/0911.5012
    Neutrino Condensate as Origin of Dark Energy
    Jitesh R. Bhatt, Bipin R. Desai, Ernest Ma, G. Rajasekaran, Utpal Sarkar
    5 pages
    (Submitted on 26 Nov 2009)
    "We propose a new solution to the origin of dark energy. We suggest that it was created dynamically from the condensate of a singlet neutrino at a late epoch of the early Universe through its effective self interaction. This singlet neutrino is also the Dirac partner of one of the three observed neutrinos, hence dark energy is related to neutrino mass. The onset of this condensate formation in the early Universe is also related to matter density and offers an explanation of the coincidence problem of why dark energy (70%) and total matter (30%) are comparable at the present time. We demonstrate this idea in a model of neutrino mass with (right-handed) singlet neutrinos and a singlet scalar."
     
  8. Nov 29, 2009 #7
    Re: Observable QG effects in Chern-Simons gravity--Stephon Alexander

    So what would be the cc w/o this neutrino condensate?
     
  9. Nov 29, 2009 #8

    marcus

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    Re: Observable QG effects in Chern-Simons gravity--Stephon Alexander

    Anybody who wonders about this would do well, I think, to watch the 1hour video:
    http://pirsa.org/09110138/
    Stephon explains the whole idea. Michael Peskin is there grilling him with questions, and also Neil Hurok the director of PI, a cosmologist. It is a risky idea. But it gets good people's attention and intrigues them.

    It assumes that there are a lot of neutrinos in the early universe, produced somehow by some reactions. Neutrinos naturally form a condensate, just like the electrons in a superconductor pair up. With electrons in superconductor, two fermions combine to make a boson. In Stephon's model four neutrinos get together. It is only a rough analogy.

    You are asking "what if there wasn't this condensate?" In that case the cosmo const would I believe be ZERO, in this model universe. In this model there is no other source of the dark energy.

    Lots of things could go wrong. There might not have been enough neutrinos in the universe to make this happen. And maybe neutrinos do not actually condense into foursomes the way he thinks they might.
     
  10. Nov 29, 2009 #9
    Re: Observable QG effects in Chern-Simons gravity--Stephon Alexander

    Does QFT calculation of cc differ from observation by 10^60? Does this condensate offset it?

    How close are Stephon's ideas to


    http://arxiv.org/abs/0911.5012
    Neutrino Condensate as Origin of Dark Energy
    Jitesh R. Bhatt, Bipin R. Desai, Ernest Ma, G. Rajasekaran, Utpal Sarkar
     
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