German Physicists Claim Speed of Light Broken 429
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.
quantum spin (Score:3, Interesting)
Every couple of years (Score:5, Interesting)
Nothing new.. (Score:4, Interesting)
Since imaginary speed waves die out over long distances, for which we do need "faster than light" speed, we will not be able to use this effect.
measuring nanoseconds (Score:3, Interesting)
Re:Another explanation from Ars (Score:5, Interesting)
Re:Every couple of years (Score:3, Interesting)
Re:Actually (Score:3, Interesting)
Randomness established? What experiment could possibly establish randomness? I'm with Einstein on that one.
Re:quantum spin (Score:3, Interesting)
Which is all decidedly strange. It's almost like we're living in an approximation running on a superscalar processor...
Re:186,000 miles per second (Score:2, Interesting)
Light faster than the speed of light. (Score:2, Interesting)
If you have a light which is traveling faster than the speed of light, then isn't there a simple test that can be done to determine if this is actually happening or not? Arrange the light source and a viewer at a distance apart where the speed of light can be empirically measured. Maybe 2 light second apart, so 599584916m apart. Have the viewer remotely start the light source with something such as a laser. If the viewer can see the light turn on in less than 2 seconds, then the light is traveling faster than 299792458m/s. Otherwise, it will take 1 second for the remote signal to reach the light source, a few ns to turn on, and 1 second for the light to get back to the viewer.
If this was legit, it'd be a great experiment for NASA as they could decrease the lag on their games...er..space ships.
Re:Photons do not have mass (Score:3, Interesting)
But since p=mv anything with momentum does have mass.
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.
if p=E/c and p=mv then mv=E/c. Since v=c; mc=E/c => E=mc^2. So the original argument stands. Now I have no illusions that i'm smarter than Einstein, but this is basic algebra and I don't see how it can be wrong. What's going on here?
Talk about old news... (Score:4, Interesting)
There's even been coverage about his tunneling experiments occasionally in the nightly show "Space Night" broadcast on the German TV station "Bayern Alpha" http://www.br-online.de/wissen-bildung/spacenight
Somehow this experiment keeps turning up now and then, causing wild speculation and discussions every time.
Re:It's sorta like this (Score:3, Interesting)
I've never understood this explanation since it uses gravity to describe gravity.
1. Placing a weight on a rubber sheet causes a distortion in the rubber sheet because gravity is pulling it down. Without gravity the weight would just sit at the position it was placed (assuming zero velocity) with no distortion.
2. A stationary ball placed on the sheet will be pulled into the well by gravity. If there were no gravity the ball will just sit where it is placed even though there is a distortion in the sheet.
So it seems to me that this model does not show that gravity is a simple distortion - it just shows that a distortion combined with some "downward" force can be used to model gravity (with no explanation as to what that downward force might be).
Re:The summary leaves only one question (Score:4, Interesting)
The real twist here is that for an object to be accellerated past the speed of light, that object would actually 'see' the rest of the universe travelling backwards, and would arrive at its destination younger than it was when it left... so it'd simple appear to us as if the packet had travelling from the 'destination' to the 'source', at a speed below the speed of light... objects travelling faster than the speed of light, and objects travelling below it, appear indistinguishable to us.
(or something like that
Re:Wrong about microwave photons (Score:3, Interesting)
Damn..I should write a book about this..
Cheers!
Re:quantum spin (Score:3, Interesting)
However, this hypothesis is actually partially testible because it implies that, if we can separate quantum particles without entangling them based on forcing them to choose paths based on states, that this should break the entanglement. I.e. if an entangled photon pair is forced to choose different fiberoptic paths based on differences in the refractive index of a part of the fiber optic cable, and this is dependant on the polarization of the photon, then we would expect under the Copenhagen interpretation either for the photons to take both paths, but for any entanglement to be broken (i.e. 2 entangled photons would take 4 paths, but be unentangled at the end).
If on the other hand, the photons have interndependant but definite states, we would expect them to remain entangled at the end and only take 2 paths. I suspect this is the case because we know that manipulations on one part of the entangled pair are transferred and this would only impact one side of the equation.
Is information transferrance the fundamental problem? Or is it simply the fact that we don't know how to do this without reentanglement? If we can be confident about the state of a particle at one point, does this preclude entanglement absent some other means?
As the author of the New Scientist story... (Score:2, Interesting)
But if you want to get more geeky, you don't even need to use any quantum mechanics or even relativity to explain what Nimtz is observing. You can also explain it using good old classical physics. What Steinberg is saying is that the microwave, which is a packet of some finite size, gets slightly delayed as it hits the edge of the prism. There's a component of the wavefront that continues propagating into the gap past the reflective surface. (Technically, this is called the wavefront's "evanescent mode" -- meaning it has a wavelength measured in imaginary numbers... so there's no physical wave in this region of space.) And if there's a small gap separating the two prisms, the wavefront returns to the physical world, with a real wavelength again, back inside the second prism. That's what quantum physics would call "photon tunneling." The seemingly faster-than-light transmission speed is just the consequence of the wavefront's being slowed down at the boundary between prism and air. So the sum-total of time the wavefront spent in transit seems faster-than-light when you only look at one portion of its overall trip. But other portions of its trip (i.e. at that boundary between prism and air) were being slowed down.
Of course to explain this in all its gory detail -- and I've kind of done a butcher job here -- requires a lot more words than we had room for in this piece. So the train analogy had to do.
The other thing, to get even more geeky -- and extra-credit is definitely awarded to anyone who picked this up in the story -- there is no such thing as 33 cm microwaves. (Wavelength too long.) That's a typo. It's 33 mm.
Consider this a big ol' nerdy D'OH!