Hi Frank, re. solitons:
To provide some general background, solitons
are waves propagating in a nonlinear medium which
have the property of maintaining their shape over
extremely long distances. They also have the feature
of colliding elastically, so that if two solitons hit
each other, they do not coalesce into an ugly blob,
they reappear (possibly with the faster one overtaking
the slower one) with exactly the same shapes they
had before the collision.
Because of their shape invariance, communications with
solitons means that the need for repeaters is
essentially eliminated. In the mid-80s, Bell Labs conducted
a number of experiments on optical communications
with solitons. However, at a later time, erbium doped
amplifiers cam upon the scene, and the cost of
repeaters was drastically reduced. At the current time,
I believe that solitons are considered primarily for undersea links (I seem to recall plans for deploying
an undersea cable using soliton in Japan).
While Russia has a strong school of mathematical
physicists working in the area of solitons, the US
and Japan have always had very strong researchers
in this area. Solitons can exist not only in
an optical context, but as Frank points out, in any
medium supporting waves (the first observation
of solitons was in shallow water canals in England
during the second half of the 19th century).. The
main difficulty with creating solitons is that
the medium must be nonlinear, which implies
complex manufacturing procedures. Also exciting
specific soliton modes is difficult.
Otherwise, solitons provide an elegant mechanism
for extremely high rate digital communications.
I do not believe that SilkRoad's stuff has anything
to do with solitons. At some point ahahaa mentioned
SilkRoad relies on new solutions of the wave equation.
As surprising as this statement may appear to some,
it did not sound extravagant to me. Approximately
10 years ago, some new solutions were identified,
which have the property of remaining coherent in time
and space over fairly large distances, until they
ultimately decay. These solutions are very difficult
to generate, but form the basis for what some
have called ``electromagnetic bullets.' The
idea of electromagnetic bullets is to aim an extremely
intense electromagnetic burst at the electronics of
incoming ICBMs, thereby destroying all the on board
electronics. This is all hush-hush, but I would not
be surprised if this stuff has been deployed. These
waves also exist in all media (I saw an acoustic
demonstration), but they are not solitons, since
they require a linear medium.
Best regards,
Bernard Levy |
