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Scientists claims light speed barrier broken

  1. Aug 16, 2007 #1
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  2. jcsd
  3. Aug 16, 2007 #2
    I find this article sketchy, light travels at 186,000mps so traversing just 3ft would seem instantanoues to most, if not all.
     
  4. Aug 16, 2007 #3

    ZapperZ

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    Oh no, no, no, no... not that superluminal tunneling AGAIN!

    Zz.
     
  5. Aug 16, 2007 #4

    SF

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  6. Aug 16, 2007 #5
    I'm a newb at physics, but i do understand the basic concept of Quantum Tunneling, so my question is. Is this just phooey?
     
  7. Aug 16, 2007 #6

    ZapperZ

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    Ah, thanks.

    So, is it me, or did the authors conveniently omitted to show any data of the results? All they did was mentioned the results, but what about the signal of both the transmitted and reflected, especially done at various angles? I'd like to see the signal. This "paper" has in fact very little of the actual results that we can actually look at.

    If I were the referee, I'd send it back.

    Zz.
     
  8. Aug 16, 2007 #7

    JesseM

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    From what I understand Nimtz's experiment actually has nothing to do with quantum tunneling, it's an effect based purely on classical E&M which is only analogous to quantum tunneling in the sense that the strength of the wave drops off exponentially as it passes through a barrier (on another thread someone mentioned that this effect goes by the name evanescent coupling). See this blog post by a physics postdoc in Germany, for example, or this paper by Nimtz himself. And of course classical E&M, being Lorentz-symmetric, can never allow genuine FTL signals.
     
  9. Aug 16, 2007 #8
    I like this explanation (simple):

    "3) In all cases of superluminal tunneling, the pulse that emerges from the tunnelling process is greatly attenuated, and "front-loaded" -- only the leading edge of the incident pulse survives the tunnelling event without being severely attenuated to the point that it cannot be detected. If we measure the speed by the peak of the pulse, it looks faster than the incident pulse. But that is just an artefact of our definition of speed as marked by the arrival of the peak in the pulse."

    http://scienceweek.com/2004/sa040618-5.htm
     
  10. Aug 16, 2007 #9

    mgb_phys

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    They haven't transmitted any information faster than light they have either misunderstood the difference between group and phase velocity (unlikely) or they or their PR dept have slightly sexed-up the report.
    It's still an impressive distance to couple an effervescent wave through.
     
  11. Aug 17, 2007 #10
    Ok, that article is true and not true at the same time, that reminds me of some QM ideas, nvm. The problem here is that the experiment is a "non locality" effect, as they were many, including the famous transportation of quantum states of IBM and many others in the last 30 years. It is a misunderstood use of language about speed or velocity in non locality, i will elaborate this, just one more thing special relativity maxima of nothing can beat speed of light in vacuum is still valid for "locality".

    Well since 1932 there was an interesing idea released on an article of a paradox, the EPR (Einstein, Podolsky and Rosen). In there it was stated "the spooky action at distance". Time passed and John Bell, made a impressive intuitive calculations, which lead to Bell theorem, it explained EPR paradox quite well, and it lead to quantum entanglement and other ideas after it.

    Lets just look at quantum entanglement that is easier to "buy" the first time you hear about it, it states that 2 particles who share the same past, are quantum entangled(mixed), that means if further in time that particle is separated any distance if you somehow modify it, the "quantum states" transport "iinstantaneously" to the other entangled particle that can be very very far away. Physics have been aware of such effect since a 30s, yet many possible explanations were given like "hidden variables" or "many worlds".

    But around 1960 Bell came and made the Bell inequity(that later became a theorem), in which stated that no "locality" theory of physics can explain Quantum effects. There were around 30 years of experimentation and validation of that theory. All quantum calculations are on a non locality state, that is why you can think about poor schrödinger cat that is half a live and half death, yet, when you take the measure you are getting into a local state, so the cat is either alive or death but not both.

    So when we are talking about quantum ideas, the problem is that we are refering to a non local reality where speed doesnt make much sense. So if you look to those quantum experiments, nothing can travel faster than light, yet at the same time quantum entanglement allows you to transportate information instantaneously.

    Now the beauty of those theories comes in black holes (and other similars, that once were called by mistake singularities). Is it possible that quantum entanglement is happening at the domain wall so quantum information from inside states is going to outside as Hawking radiation? If so how would that look like?, what about the temperature of the states specially its spectrum?
    Those answers will lead us to some very important understanding of quantum gravity and perhaps we would be able to declare LQG, M-theory, Casual sets or another the winner.
     
    Last edited: Aug 17, 2007
  12. Aug 17, 2007 #11
  13. Aug 17, 2007 #12

    >> Scientists claims light speed barrier broken

    It has been broken long time ago
    But the question is, can you send infomation/message faster than the speed of light;
    For example, you can not send information using quantum entanglement which can travel faster than the speed of light
     
    Last edited: Aug 17, 2007
  14. Aug 17, 2007 #13
    I agree you cant send information but you can send the configuration of quantum states, so one could think i am sending information via quantum states, but the deal is that the information was already there.
     
  15. Aug 20, 2007 #14
    Nimtz & Stahlhofen - a few details

    Keep in mind this hasn't been published yet, so this isn't "the whole ball of wax", from what I understand the version the link below takes you to amounts to preliminaries still under review.

    I.e. "lets not have a cow man" ;-) , at least not yet.

    That said, a careful reading does offer a few tantalizing details worthy of chewing on that *I* haven't seen anywhere else, and since everybody seemed to have questions about things omitted (conveniently or not) in most of the coverage in the lay press, I'm hoping this will answer at least some of those questions.

    http://arxiv.org/ftp/arxiv/papers/0708/0708.0681.pdf

    Thoughts?
     
  16. Aug 20, 2007 #15

    pervect

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    I've merged this with the existing thread.
     
  17. Sep 1, 2007 #16
    Okay, why do people assume that if something travels faster than the speed of light that it arrives at its destination instantly OR EVEN that it arrives before it left in the first place???? In the universe Light is slow compared to the distance it must travel, that is why we refer to "10 billion light years" making a references as to the distance an object traveling at the speed of light would cover. If that object traveled faster even by 2 Miles per second that is just a little bit faster and would be considered "faster" then the normal speed of light yet over it's distance still make little to no difference as to the time that light would get from point A to B. If it takes 10 Billion Light years to get from point A to point B and you travel 2X the speed of light, would you arrive there instantaneously or should you get to point B in 5 billion years instead of 10?

    When ever we have experimented with particles traveling "faster then the speed of light" the results show that be "package" arrived before the button was pushed for it to leave. Maybe because we do not have equipment advanced enough to calculate how fast this is actually going. The results them selves would have a delay time for christ's sakes! Even a Fiber Optic machine would have a delay time in measuring results if what it is in fact testing goes faster then it can even transfur or capture data.... Of course the results are scewed. Maybe thats why.

    Can't Light travel faster then it normally does anyway when it bends around a big gravitational field like a black hole but doesn't get caught? Kind of like how a Meteor gets caught in Jupitors grav. field and gets flung out the other side even faster? Light speed anomalies have happened.
     
    Last edited: Sep 1, 2007
  18. Sep 1, 2007 #17

    Hurkyl

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    Because it's a fairly easy geometric fact of Minkowski space-time that if something travels faster than the speed of light, there are inertial coordinate charts where it travels instantaneusly, and there are inertial coordinate charts where it arrives at its destination before it leaves its origin.
     
  19. Sep 2, 2007 #18

    XVX

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    I researched this slightly and found this Nimtz has been at this for at least 10 years!

    G. Nimtz:
    www.public.asu.edu/~strato/Internet/Evanescent modes G Nimtz.pdf

    His only collaborators. Notice the title.
    www.public.asu.edu/~strato/Internet/Photonic tunneling Z Wang.pdf

    I don't think it's stated in this paper, but Nimtz said something about transmitting a Mozart symphony faster than light and this guy directly attacks that statement in the end.
    www.public.asu.edu/~strato/Internet/Faster than light A. Fettweis.pdf

    There are lots of papers refuting this guy and I don't see that many accept his interpretation of events.
     
  20. Sep 4, 2007 #19
    So am I to understand that photonic tunneling is bs? I assumed that nimitz more or less just transferred information between two photons but not the photons themselves?

    Now I'm more confused than I started!
     
  21. Sep 4, 2007 #20

    mgb_phys

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    No tunneling is real - what this guy was claiming, at least in an earlier version, was basically the difference between group and phase velocity. Phase velocity can go faster than light but doesn't carry any information.

    As a simple analogy, imagine that the front edge of a photon can spread out forward and arrive before the middle of the photon (which is traveling at the speed of light) - so you have a photon going faster than light. But you can't be sure the photon is there until you have the trailing edge so to transfer any info you have to wait for the whole photon to arrive = the speed of light.

    (ok it's an over simplisitic ie. wrong explantation)
     
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