16
October 2003
Relativity: The ultimate speed limit
Ever since Einstein proposed the special theory of relativity there has been continued interest in determining whether the speed limit of objects is equal to c, the speed of light in a vacuum. So, not surprisingly, reports that the group velocity (the velocity of the envelope of a group of waves of nearly equal frequencies) of light pulses can exceed c provoked widespread discussion. Stenner et al. now demonstrate for the first time that the speed of information is less than c for pulses travelling in a medium where the group velocity exceeds c. This work confirms the ultimate speed limit and suggests methods for speeding up communication systems to approach this limit.
The speed of information in a 'fast-light' optical
medium
MICHAEL D. STENNER, DANIEL J. GAUTHIER & MARK
A. NEIFELD
Nature 425, 695–698 (2003); doi:10.1038/nature02016
| First
Paragraph | Full
Text (HTML / PDF) |
