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Science Technology

German Physicists Claim Speed of Light Broken 429

Posted by ScuttleMonkey
from the don't-believe-your-optics dept.
Byzanthy writes "Two German physicists claim to have broken the speed of light by using 'microwave photons.' According to Einstein's special theory of relativity, it would require an infinite amount of energy to accelerate any object beyond the speed of light. However, Dr Gunter Nimtz and Dr Alfons Stahlhofen, of the University of Koblenz, say they did it by using a phenomenon known as quantum tunneling. The pair say they have conducted an experiment in which microwave photons — energetic packets of light — traveled 'instantaneously' between a pair of prisms that had been moved up to 3ft apart." New Scientist, however, is running an article that suggests Einstein can rest easy. Aephraim Steinberg, a quantum optics expert at the University of Toronto, explains that the German physicist's results aren't necessarily wrong, they are just being interpreted incorrectly.
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German Physicists Claim Speed of Light Broken

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  • by Ancient_Hacker (751168) on Friday August 17, 2007 @09:40AM (#20260177)
    Oy vey, how likely the article is accurate if they get the basics wrong?

    "Microwave photons" are neither "light", nor "energetic".

    Photons with a frequency in the microwave region are thousands of times less energetic than the least energetic light photon. Basic Plank's equation, E = hv, you see.

    And Einstein need not worry, his basic theory or Relativity covers the fuzzy concept of "simultaneity" and "instanteinity" quite thoroughly.

  • Re:quantum spin (Score:3, Informative)

    by vigmeister (1112659) on Friday August 17, 2007 @09:43AM (#20260207)
    This is called the EPR paradox [wikipedia.org] and IIRC it was forwarded by Einstein himself to demostrate the quantum physics yielded BS results. I don't think it is now considered a real paradox since information still cannot be transmitted faster than light.

    Cheers!
  • Incredible? (Score:5, Informative)

    by vigmeister (1112659) on Friday August 17, 2007 @09:46AM (#20260259)
    Something like this was claimed a while back. Is it like this guy's [wikipedia.org] experiment where although an adge of a light pulse travelled faster than light, information still could not be transmitted faster than light?

    Not discrediting the achievement. This will help us clarify current theories regarding speed limits and stuffz

    Cheers!
  • Re:Actually (Score:5, Informative)

    by brunascle (994197) on Friday August 17, 2007 @09:48AM (#20260287)
    i think you're confusing quantum physics and relativity. Einsten didnt believe in, and tried to disprove, quantum physics, but i dont believe he ever questioned his own relativity theory.

    "God does not play dice" is about the inherent randomness in quantum physics.
  • by tomz16 (992375) on Friday August 17, 2007 @09:51AM (#20260331)
    No it wasn't... (look up group vs phase velocity)
  • Re:Actually (Score:3, Informative)

    by krgallagher (743575) on Friday August 17, 2007 @09:54AM (#20260369) Homepage
    "Einstein died thinking his theory was the "dumbest thing since ...I do remember his "God does not play dice" statement."

    Actually that quote is from a letter he wrote to Max Born [wikipedia.org] about his distrust of the theory of quantum mechanics, not his own theory of relativity. Here [wikiquote.org] is the actual quote:

    Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the Old One. I, at any rate, am convinced that He does not throw dice.
  • by eyebits (649032) on Friday August 17, 2007 @09:56AM (#20260393)
    Photons do not have mass.

    From: http://imagine.gsfc.nasa.gov/docs/ask_astro/answer s/960731.html [nasa.gov]

    The Question
    (Submitted July 31, 1996)

    Do photons have mass? Because the equations E=mc2, and E=hf, imply that m=hf/c2 . Is it so?

    The Answer
    No, photons do not have mass, but they do have momentum. The proper, general equation to use is E2 = m2c4 + p2c2 So in the case of a photon, m=0 so E = pc or p = E/c. On the other hand, for a particle with mass m at rest (i.e., p = 0), you get back the famous E = mc2.
  • Re:quantum spin (Score:4, Informative)

    by Skrynkelberg (910137) on Friday August 17, 2007 @09:58AM (#20260417)
    You're thinking of the EPR Paradox [wikipedia.org].

    Simplified, when you have two entangled electrons and measure the spin along an axis of the first, the second one immediately takes on the opposite spin of the first.

    But you don't know what spin you are going to get by measuring the electron; because it is made of two entangled wavefunctions it's pure chance which one is going to show up. Thus, you have no control over which spin the second electron has, and thus you can't transmit any information using this phenomena.

    However, you DO know the spin of the second electron, a fact that can be used. For example, you can create potentially unbreakable ciphers using Quantum Cryptography [wikipedia.org].

  • Re:Idiocy (Score:2, Informative)

    by MrNaz (730548) on Friday August 17, 2007 @10:01AM (#20260463) Homepage
    Actually no. The word "light" is used to represent the subset of the electromagnetic spectrum that corresponds to EM radiation in the range that results in visible light. Scientifically, the word "light" has no definition, however most people use the word to refer to its vernacular reference to visible EM radiation. Now don't bother going on the net to find some site that defines it differently. I know you'll find one, but that's because the word's meaning is unduly broad and also because it is so commonly misdefined.
  • by kebes (861706) on Friday August 17, 2007 @10:04AM (#20260497) Journal
    Indeed. Now, I won't say with certainty that this present claim is wrong... but we've seen so many "speed of light broken!" reports over the years that I'm not going to get too excited. Typically, when people think they have seen a speed-of-light violation, they are actually reporting on one of two well-established phenomena:

    1. Group velocity versus speed-of-light. Basically, relativity states that no individual photon can travel faster than c. However a collection of photons interfere to form a beam or a pulse with some kind of shape. You can arrange your experiment so that the envelope of the pulse travels at some velocity (faster than light, slower than light, etc.) but the individual photons are still always traveling at exactly c.

    2. Quantum instantaneousness. Two particles can be put into a quantum entanglement, such that their states depend on one another, even though they have not 'picked' a particular state yet. You can separate the two particles (even by a huge distance), collapse one particle into a state and the other particle collapses instantaneously into the corresponding state. This instantaneous effect seems to violate the light-speed rule. However because the experimenter cannot control the state which is selected upon collapse, no "information" is actually transmitted from one location to the other.

    Importantly, both 1. and 2. involve emergent effects that a human may characterize as "faster than light"--but no information, and no energy, was transmitted faster than light-speed. (And, to be clear, relativity states that energy and hence information cannot travel faster than light. Emergent phenomena can travel at arbitrary speed. In fact in relativity spacetime itself can, theoretically, expand faster than light, but you still can't send signals from one location of spacetime to another at greater than c.)

    From the descriptions, it really does sound that these researchers are merely committing one of those two classic fallacies (or maybe a novel combination of the two?). Now, assuming that these researchers are not novices, I find it hard to believe that they would commit such classic mistakes. So in this case it might be a subtle point to prove that relativity is not disproved, but my assumption would be that they have made a mistake somewhere.

    I don't mean to dismiss these results, and new science certainly comes from violations of established science. However relativity is so well-established at this point that making the extraordinary claim "we've violated relativity" is going to require exhaustive verification.
  • I thunk.. (Score:3, Informative)

    by toQDuj (806112) on Friday August 17, 2007 @10:08AM (#20260539) Homepage Journal
    I thought that something travelling at exactly the speed of light required infinite amounts of energy. No-one said anything about more than the speed of light.

    Check out what happens when X-Rays pass the speed of "light" in water. check out Cherenkov radiation. Irregularwebcomic has a good explanation http://www.irregularwebcomic.net/1636.html [irregularwebcomic.net]

    B.
  • Re:I thunk.. (Score:3, Informative)

    by CaffeineAddict2001 (518485) on Friday August 17, 2007 @10:26AM (#20260757)
    It takes infinite amount of energy to accelerate something to the speed of light. It's theoretically possible for something to travel faster than light if it somehow had just popped into existence at that speed (How that would happen I have no idea).

    As for Cherenkov radiation, the speed of light is only constant inside a vacuum.
  • by oh_my_080980980 (773867) on Friday August 17, 2007 @10:27AM (#20260785)
    It just goes to show that journalists have a hard time reporting science.

    The Speed of Light limitation is in regards to Matter, i.e. something with Mass. A Photon does not have mass. The component is acceleration! You cannot accelerate matter faster than the speed of light. The reason being as you begin to approach the speed of light, the object in question begins to increase in mass. Thus you need increasingly more energy to propel the object. More energy, continues to increase the mass of the object.

    However there is no law against objects that already travel faster than the speed of light. For example, Tachyons. Hypothetical particles that travel faster than the speed of light. However they have never been found.

    So a Photon can travel faster than itself - i.e. speed of light because it has no mass. Interesting. The explanation of why it's wrong doesn't jive. The data still prove it got there faster than it should.

    Theoretical Physicists have a hard time with Experimental Physicists, mainly because experimental physicists have data to backup the arguments.

  • Re:Actually (Score:5, Informative)

    by rk (6314) on Friday August 17, 2007 @10:42AM (#20260993) Journal

    Then there's Hawking: "Not only does God play dice with the universe, He sometimes throws them where you can't see them."

  • It's sorta like this (Score:5, Informative)

    by Moraelin (679338) on Friday August 17, 2007 @10:50AM (#20261099) Journal
    It's sorta like this:

    1. First of all, the somewhat inaccurare version Newtonian version: when you calculate the acceleration of a small body in the gravity field of another body, the small body's mass cancels itself out.

    I mean, the force is: F= G * M * m / d^2

    The small body's acceleration therefore is: a = F / m = G * M / d^2

    You'll notice that the small body's mass isn't present at all in the acceleration, which in this case is also determining the curvature of the trajectory. Or to put it otherwise, a 1g thumb tack will fly in the exact same orbit as a thousand ton Goa'uld pyramid. As you make mass smaller and smaller, in other words take a limit when mass -> 0, well, the trajectory still stays curved.

    2. Actually, in a perverse way, you are right that Newtonian mechanics should not apply to light, and they don't: if you apply Newtonian mechanics to light, the predicted deflection of light is only half the deflection actually observed. So light does act funnily in a gravity well.

    Light's curvature in a gravity well is only explained right by Einstein's general relativity. There gravity is just the observed consequence of a distortion of space itself. The presence of a mass there distorts space. The usual analogy is that it's like having a horizontal rubber sheet and placing a steel ball upon it. You'll get an indentation in the sheet. The effects on other nearby bodies, or on their movement, is basically just the consequence of that distortion of space.

    And so it is with light too. It's not as much that newtonian gravity pulls it, as just that it's moving through a warped piece of space.

    3. Generally, don't try to apply your RL intuition and experience to relativistic or quantum phenomena, it tends to just fail spectacularly :)
  • Re:I thunk.. (Score:3, Informative)

    by Guppy06 (410832) on Friday August 17, 2007 @11:32AM (#20261723)
    "I thought that something travelling at exactly the speed of light required infinite amounts of energy. No-one said anything about more than the speed of light."

    It takes an infinite amount of energy to get something with real mass (tardyons) to reach the speed of light in a vacuum. Photons (luxons) do it by not having any real mass, only momentum. And, looking strictly at the math of special relativity, it would also require infinite energy for something with imaginary mass (tachyons) to slow down to the speed of light in a vacuum.

    "Check out what happens when X-Rays pass the speed of "light" in water."

    The speed of light through water is less than the speed of light through a vacuum, which is the important number (and why light is refracted when it hits the surface of water)
  • She doesn't know it because information will take several minutes to get there, but her state changes instantly.

    Without getting bogged down in the specifics of your thought experiment:
    According to General Relativity, her state does not change "instantly".
    According to Quantum Mechanics, her state does change "instantly".

    This is the essential problem in modern physics. General Relativity and Quantum Mechanics are, as they stand, in contradiction with one another.
  • by eyebits (649032) on Friday August 17, 2007 @12:11PM (#20262445)
    Hatta said: But since p=mv anything with momentum does have mass.
    No. Logical fallacy. If p then q does not mean q then p. Ex: Boys have eyes. So, if a person has eyes is that personal necessarily a boy?

    p = mv is true if there is mass that is moving. Without mass, given only that formula, there would be no momentum. But it is also true p = E/c. If an entity has energy it has momentum. The momentum can come from a mass with velocity or from energy. To say that an entity with momentum has mass because p = mv is not logical because the momentum may not have come from the entity having mass it may have come from the entity having energy. Photons have no mass but they do have energy.

    Wikipedia - momentum - http://en.wikipedia.org/wiki/Momentum [wikipedia.org] (scroll down to "Momentum of massless objects")

    Wikipedia - photon: http://en.wikipedia.org/wiki/Photon [wikipedia.org]
    Planck's Constant and Energy of Photon - http://www.colorado.edu/physics/2000/quantumzone/p hotoelectric2.html [colorado.edu]
    Relation of Photon Energy and Frequency - http://www.physlink.com/education/AskExperts/ae99. cfm [physlink.com]

  • Re:I thunk.. (Score:3, Informative)

    by CaffeineAddict2001 (518485) on Friday August 17, 2007 @12:25PM (#20262765)
    Photons are particles. It happens when a *charged* particle exceeds the speed of light (Electrons). Photons are not charged.
  • by udippel (562132) on Friday August 17, 2007 @12:30PM (#20262895)
    I'm a n00b, or a non-quantum guy. So this may be stupid.

    Don't worry. You're in /. Here we all are n00b, non-quantum or simply stupid. Welcome to the club.

    Galileo proposed quite exactly what you do: uncover a lantern (or better two) postioned on two hilltops.
    599584916m, though, made me smile. 599584 km and 916 m isn't quite that simple.
    And now to the core: you didn't read the article, did you ? They never suggested what you propose. They simply 'bridged' a distance of less than 1 m. But what they observed, was, that irrespective of that distance of up to 1 m, the light travelled in zero time. At least, they couldn't measure it. At least, it did take much less time than your 1/299792458 would require it to take.
    And, they didn't observe it like for a beam that your torch would produce, but for few particles of that beam only.

    Personally, I think they're nuts. They confound group and phase velocities.
    Before you ask, here comes my explanation: A large group of drunkards has thrown the corks of their wine bottles into the sea, at incoming tide. The corks dance up and down on the waves; slowly attaining the beach. Then, waves break. When they do so, a whole wave front rolls over. To you, as standing on the beach, the peak of the rolling wave either spreads quickly to the left or right, depending on the incoming angle. The breaking of the in-rolling waves spreads quickly; one may as well say, that its phase instance propagates relatively fast to the left or right. If need, walk down to your next beach and observe how fast the state of the waves spread across the waves rolling ashore.
    That's 'phase speed': the propagation of the same phase (rolling over).
    What's that 'group speed' now ? Simply: the speed with which the corks are closing in on the beach. They're dancing up and down; the states of their phases propagate quickly. But their 'information', their physical existance, approaches the beach relatively much more slowly.
    The rolling-over of the phase might propagate by several meters per second. The actual approach of the corks towards the beach can as well be as slow as a few cm per minute.
    Einstein's speed of light applies to the light itself; in our example the corks. While propagation of the same phase is nothing but a maya; a virtual and artifial 'speed'.
    What those chaps observe is nothing but the latter: Some phase arrives on the other side of the gap as quickly as if there was no gap at all.

    That much what a stupid non-quantum n00b has to add to your implied question.
  • Re:Nothing new.. (Score:2, Informative)

    by Anonymous Coward on Friday August 17, 2007 @12:30PM (#20262911)
    Right.

    This is well known. Light transmitted from one prism to another via evanescent waves does not "move" through the air gap. It quantum tunnels and the effect is instantaneous, but there are NO photons moving in the air gap, so nothing is moving faster as the speed of light. The prisms have to be very close together, because light wavelengths are small.

    I'd include this in my lectures on evanescent waves all the time.

    What is new here is that they did it with microwaves, so they could use huge wavelengths and demonstrate an old old effect with an appreciable distance (1 meter).

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