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Light so Fast it Travels Backward
An anonymous reader writes "Slowing down light used to be considered a neat trick for physics wonks. But researchers in New York now say they've pushed light into reverse. And as if to defy common sense, the backward-moving light travels faster than light." While there's not much use to come of it yet, it will be interesting if Einstein himself is proved wrong.
...just shift the ship's gear into R...
With the faster than light part, the key word here is "information". Quantum tunnelling achieved faster than light travel of particles, but the information is lost, where information can be a bit pattern or the hotly debated signal with Beethoven's 5th. As far as I know, they never really managed to send Beethoven's 5th and then receive it on the other side.
Why is the light travelling faster than light? It has to do with quantum probabilities, where the particles sometimes appear on the other side of the barrier as if the barrier wasn't there. Its like the space where the barrier was is just removed, so the particle actually travels a shorter distance than would be measured from the reference of the observer. The particles are actually moving at the same velocity on both sides of the barrier, but since they skip through the barrier, they actually arrive before regular light would.... or at least that was how I understood it.
Since the particles end up on the other side of the barrier only sometimes (depending on the probability) the researchers haven't found a way to send any relavent information that can withstand the randomization.