As long as we're playing "Who Wants To Be The Most Technical", I'll go ahead
and add my own
entry...
--- [EMAIL PROTECTED] wrote:
> But always: "phase velocity" = frequency times wave length at each particular
> frequency.
> However, the "group velocity" of a packet of waves of many frequencies which
> superpose to form
> pulses of various shapes can range from near zero to very large numbers, but
> *always* less than
> c = 3 x 10^m/s.
Nope. I refer you to:
Matthew S Bigelow, Nick N Lepeshkin, Heedeuk Shin, Robert W Boyd, “Propagation
of a smooth and
discontinuous pulses through materials with very large or very small group
velocities”, Journal of
Physics: Condensed Matter. 18, 3117-3126 (2006)
I don't think group velocity is necessarily equivalent to the velocity of
propagation of
information. It can be greater than c, or even negative, in cases where large
anomalous
dispersion is present.
[Note: once AGAIN I forgot to send to the whole list. Apologies!]
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