Faster than Light... Superluminal Group Velocity

[ThunderLight]

If general relativity in the formal sense constrains all velocities to the speed of light as a maximum, how would superluminal group velocities exceeding speeds of light (at their superpositions) be evaluated in mainstream physics? Would this be a case of General Relativity and Physics principles Violation?

An example is a paper reporting superluminal group velocities measured:
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.88.073901

 

[ZapperZ]

This is an awfully old news. This, and the NEC experiment from way back (https://www.physicsforums.com/threa...n-the-speed-of-light.98696/page-2#post-819155) that has been discussed extensively on PF, are NOT breaking SR and GR. These are done in anomalous medium, and ... pay attention to this... no part of the wave moves faster than c!. This is why it is crucial to understand how we detect a wave, i.e. what part of the wave would have to reach us before we say we detect it.

Zz.

 

[fresh_42]

The question has been answered and there is no need to repeat a ten year old thread, which could as well be read instead.
FLT is a myth: debunked.

This thread is closed.