Il 24/07/2011 12:25, Giorgio Pastore ha scritto:
> Inoltre, tutte le previsioni indirettamente basate sull' esistenza di
> c come velocita' limite sono state finora confermate agli esperimenti.
la pi� recente conferma:
"Discovery of superluminal propagation of optical pulses in some
specific medium 10 years ago has evoked the world's dream of time
travel, but later scientists realized that it is only a visual effect
where the superluminal 'group' velocity of many photons could not be
used for transmitting any real information. Then people set their hope
on single photons because in the strange quantum world nothing seems
impossible -- a single photon may be possible to travel faster than
the speed limit in the classical world. Because of lack of
experimental evidence of single photon velocity, this is also an open
debate among physicists. To tackle the problem, Prof Du's team
measured the ultimate speed of a single photon with controllable
waveforms. The study, which showed that single photons also obey the
speed limit c, confirms Einstein's causality; that is, an effect
cannot occur before its cause."
<
http://www.physorg.com/news/2011-07-hk-physicists-photons.html>
<
http://dx.doi.org/10.1103/PhysRevLett.106.243602>
--
bye
!(!1|1)
Received on Tue Jul 26 2011 - 14:34:12 CEST