There is a difference between having something arrive faster than
light and transmitting information. For example, if I point a laser at
a distant wall and then turn around, I can make the spot where it
meets the wall move faster than light. But it doesn't transmit any
information from the original spot to the final one.
I'm not entirely sure about those X-waves (wonderful name, sounds
completely like Star Trek technobabble :-) they used, but previous
experiments have involved tunneling effects. In the tunneling
experiments people simply sent a signal at a potential barrier, and
measured the stuff that tunneled through it. Since quantummechanically
speaking the signal already was distributed across the entire
universe, some of it of course was already there and appeared to have
moved superluminally. I guess these X-waves do the same but in another
fashion, exploiting the difference between phase and group velocities.
http://xxx.lanl.gov/abs/physics/0001039
http://xxx.lanl.gov/abs/quant-ph/0002022
Of course, xxx is not entirely free from cracpots too. I found this
wonderful case when searching the above:
http://xxx.lanl.gov/abs/physics/9907005
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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