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Any experimental verification of superluminal communication?

Kind of.

And also here.

I can understand the group velocity argument, but what bothers me is that the rationale for 'proving' that superluminal communication can't happen seems very similar to the one that was being used to 'prove' with absolute relativistic certainty that the group velocity has to be less than c.

This doesn't 'prove' anything about what's possible, but it does make me suspicious of the rigour of the arguments that are being used.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Jan 2nd, 2008 at 04:59:35 PM EST
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Oh, that!Faster than a Speeding Light Wave - UFO Evidence
Researchers have now measured many group velocities higher than c. "It's just not true what they say in the textbooks," says Raymond Chiao of the University of California at Berkeley. For example, a Gaussian shaped light pulse can travel faster than c through some highly absorbing materials. The explanation is that the central piece of the pulse is attenuated more than the earliest piece. Although the pulse shape is unchanged, it comes out smaller, and the "leading edge" of the input pulse is transformed to become the peak of the emerging pulse, a process called "reshaping." So no part of the pulse is actually transmitted faster than c, says Chiao.
That doesn't constitute a test of superluminal transmission of information, though I can imagine an experiment being designed on the basis of this phenomenon.

We have met the enemy, and he is us — Pogo
by Migeru (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 05:24:41 PM EST
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