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Electrical Pulses Break Light Speed Record
J'raxis writes "PhysicsWeb writes that 'Pulses that travel faster than light have been sent over a significant distance for the first time. Alain Haché and Louis Poirier of the University of Moncton in Canada transmitted the pulses through a 120-metre cable made from a coaxial 'photonic crystal.' Haché and Poirier emphasize that their experiment does not break any laws of physics. Although the group velocity exceeds the speed of light - an effect permitted by relativity -- each component of the pulse travels slower than light.'"
This actually has nothing to do with bandwidth, nor will it make ftl communications possible. Think of it this way. Put in a sine wave, and it shifts it 90 degrees out of phase. So when the leading edge of the wave hits the other end, it makes it a peak, and when the peak gets there, it is at the trough of the output. It looks like the peak got to the output faster than light, but in reality it was just the leading edge of the wave being amplified.
I forgot to mention how this IS important. What this type of research will lead to is reduced latency. Instead of information traveling down a cable at 2/3 of the speed of light, they can use methods like this to send data at much closer to the speed of light. Not more data, but slightly lower ping times.
My team words just the opposite: Each individual working at breakneck speeds, but the group never gets there fast enough.
Now if they only could stop posting to /.
Free, as in your money being freed from the confines of your account.
Please forgive my lack of knowledge in this area, but what you said just doesn't make sense to me. If you can send waves FTL, and send information on those waves, then it logically follows that you can send information FTL... What am I missing?
Take a look at this applet and this page. They give a good illustration of the concept:
[...]If dn(v)/dv is sufficiently negative, it can reduce the denominator in Equation (3) to less than one, yielding a group velocity greater than c. Why is this not a contradiction of special relativity? No energy or information needs to travel at the group velocity in order for the shape of the wave to exhibit features that move at that speed. If you tried to signal someone with a superluminal pulse by dropping a shutter in its path at the last moment, you'd find you were too late: the pulse would happily "pass through" the shutter, because every influence that was actually responsible for its appearance on the other side would have passed through already.
This allows the peak of the pulse to move faster than light speed. However, the leading edge of the pulse does not.
This is why this is not a technique for sending information faster than the speed of light.