An elegant explanation of the Opera FTL results

Discussion in 'Physics & Math' started by Tach, Nov 23, 2011.

  1. Tach Banned Banned

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    The authors of this paper explain the FTL result of the Opera experiment via the fact that while neutrinos cannot exceed the light speed in vacuum while traveling in vacuum, they can exceed the light speed in vacuum while traveling in non-vacuum (like rock) due to the fact that materials present a negative refraction index to neutrinos.
     
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  3. Tach Banned Banned

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    One nice feature of the paper is that the authors reconcile the Opera results with the earlier SN1987 observations.
     
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  5. Reiku Banned Banned

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    Requires more tests then.
     
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  7. Pete It's not rocket surgery Registered Senior Member

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    Wait... would that imply FTL communication, or is this a group-velocity vs phase-velocity thing?
     
  8. Tach Banned Banned

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    No, it does not imply FTL communication. No information is transmitted at speed greater than light.
     
  9. rpenner Fully Wired Valued Senior Member

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    I believe the bet with low odds is still on "systematic error."

    http://scienceblogs.com/principles/2011/11/fast_neutrinos_still_fast.php
    http://scienceblogs.com/startswithabang/2011/11/the_new_opera_faster-than-ligh.php

    The second link looks at the data and speculates about a type of systematic error.

    I believe that the authors of the paper linked to in the OP have not mastered the propagation speed of disturbances in QFT. Rather than being an "elegant" solution, this would be like tearing up an entire room of wall-to-wall covering and dropping a tiny throw rug on the rough and exposed subflooring and calling it "elegant."
     
  10. Pete It's not rocket surgery Registered Senior Member

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    You've been to my place!
     
  11. OnlyMe Valued Senior Member

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    I heard you were tearing up carpet, but a throw rug Pete?
     
  12. Pete It's not rocket surgery Registered Senior Member

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    Of course!

    The elegant chic of a floral throw rug provides a striking emphasis that sets off the starkly primal mood of the naked concrete slab.

    ...or maybe the pressure is getting to me?
    :runaway:
     
  13. Tach Banned Banned

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    What proof do you have of that? Can you elaborate? Some specifics in the form of math would be great. After all, they are professional scientists, on faculty staff.
     
    Last edited: Nov 24, 2011
  14. rpenner Fully Wired Valued Senior Member

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    Because the propagation speed of disturbances in QFT is one. (In units where c=1).

    I don't know if this is in all the QFT textbooks, but it should be.
     
  15. Tach Banned Banned

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    But the authors clearly state:

    "An energetic standard neutrino, traveling faster than light in that medium, is expected to produce electron/anti-electron pairs that radiate away the neutrino energy. This radiation has not been observed neither with Opera [1] and Icarus [21] nor from the moon as radio signals [22]. Thus, we agree with CG (this is the Glashow paper) conclusions that Standard Model tachyonic neutrinos cannot be reconciled with the OPERA results. From this we
    suggest that Beyond-Standard Model Majorana neutrinos with imaginary mass ik obeying p ≥ kc, may fit with Opera data, when crossing a medium."

    (bolds and comments are mine)
     
    Last edited: Nov 25, 2011
  16. Reiku Banned Banned

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    Just an opinion, but I find the analog cherenkov radiation arguement a little displaced. We have never observed a true tachyonic particle so we just assume it conforms to the theories we would normally apply to them.
     
  17. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Notwithstanding the author, I agree with the conclusion.

    It appears that the theoretical speculations to support FTL neutrinos are taking a very 'ad hoc' approach, in which the neutrinos 'jump' forward at very FTL, then resume their journey at light speed (or very slightly below). I would not like to be trying to support that mathematically.
     
  18. Farsight

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    That reminds me of Gunter Nimtz and the evanescent wave, Walter. See wiki.
     
  19. Reiku Banned Banned

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    See this is the problem. If anyone claims that a tardyonic neutrino exceeded speed light to become a tachyonic particle, then this is in direct violation of Relativity. However, Relativity will allow the special case of a particle already moving at superluminal speeds.

    But then comes the question of whether an analog to Cherenkov Radiation would be observed.
     
  20. Jason Chapman Registered Senior Member

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    When we discovered that the world wasn't flat did it have a catastrophic effect on our society? Columbus pushed the boundaries and proved that because someone lays down the rules doesn't mean they are right. Ok so we were less sophisticated back then.

    The thing that has been upsetting the scientific community the most, is that scientists have based their life's work around Einstein's special theory of relativity. And now someone comes along and demonstrates that there are things that can travel faster than light. It does throw a spanner in the works for many physicists who have made a lot of discoveries in the last few decades. But it doesn't necessarily trash peoples life work.

    The genie is out of the bottle now and cannot be put back in and the question we need to ask ourselves is where do we go from here?

    no, I'm not new, its been an eon since I last posted.
     
  21. James R Just this guy, you know? Staff Member

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    It will take a lot more than this to convince the general physics community that we have an actual instance of something with mass travelling faster than the speed of light in vacuum.
     
  22. Farsight

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    Especially since mass is a measure of system energy. It's a measure of how much energy-momentum has no aggregate motion with respect to you. Trap a massless photon in a mirror=box, and you add mass to that system. Open the box and it radiates, losing mass, just like Einstein's E=mc² paper. But this is nevertheless an interesting result. For neutrinos to have a slight mass, and for that mass to oscillate, their speed has to be below c, and it has to vary. People don't always appreciate this, but apply a sliding scale to the photon in the box: moving at c = no mass, moving at an aggregate speed of zero = all mass. This just isn't what we've seen here. And if somebody finds out that neutrinos are moving at c after all, where does that leave neutrino oscillation? Where does that leave neutrinos?
     
  23. CptBork Valued Senior Member

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    If the FTL neutrino claim holds up against all cross-checks and followup experiments, then IMO the next logical thing would be to attempt a setup in which signals and neutrino pulses are exchanged in both directions, since Relativity would dictate that a time paradox occurs in such a situation unless something prevents or delays the actual exchange of information.

    In the meantime, I remember someone on this forum once pointed to an article in which it was proposed that QED vacuum effects actually produce a small decrease in the vacuum speed of light, i.e. photons in "vacuum" travel slightly slower than the true value of \(c\), in which case a result like OPERA's wouldn't necessarily be inconsistent with causal Relativity, but rather our existing definition of \(c\) would need to be adjusted a miniscule amount. I'm surprised I haven't heard any talk of such proposals in light of OPERA's findings.
     
    Last edited: Nov 27, 2011

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