Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Bass on 13/10/2005 01:24:29

Title: Solitons
Post by: Bass on 13/10/2005 01:24:29
What the heck are solitons?

I recently read an article that described them as "molecules of light".  Do they have mass?  What makes solitons different from photons?  Do regular light waves degrade over distances?

Prediction is difficult, especially the future.  -Niels Bohr
Title: Re: Solitons
Post by: neilep on 13/10/2005 02:13:35
Well Google has a lot to say about them...here's the very first link at the top of the pile http://www.ma.hw.ac.uk/solitons/   and this one http://physics.usask.ca/~hirose/ep225/animation/soliton/anim-soliton.htm  ...

....... phew !!..heavy reading !!....any chance of a watered down explanation Science peeps please ?

Men are the same as women.... just inside out !! (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.zerogain.com%2Fforum%2Fimages%2Fsmilies%2Faction-smiley-075.gif&hash=84631c0c4a382b5e68463904b7b9fddf)
Title: Re: Solitons
Post by: another_someone on 16/10/2005 22:51:46
quote:
Originally posted by neilep

Well Google has a lot to say about them...here's the very first link at the top of the pile http://www.ma.hw.ac.uk/solitons/   and this one http://physics.usask.ca/~hirose/ep225/animation/soliton/anim-soliton.htm  ...

....... phew !!..heavy reading !!....any chance of a watered down explanation Science peeps please ?

Men are the same as women.... just inside out !! (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.zerogain.com%2Fforum%2Fimages%2Fsmilies%2Faction-smiley-075.gif&hash=84631c0c4a382b5e68463904b7b9fddf)



I am not a physicist, nor a mathematician, and don't claim to understand the mathematics of it all, but do recollect reading about tidal bores, which are a particular type of soliton, many years ago in Scientific American.

One page which unfortunately no longer exists, but I qouted for someone about 2 years ago, was:

http://www.imm.dtu.dk/math_phys/Solitons.html
quote:

The soliton is regarded as an entity, a quasi-particle which conserves
it's character and interacts with the surroundings and other solitons as a
particle.



You might also wish to look up the wikipedia page on http://en.wikipedia.org/wiki/Soliton

As I understand it, a soliton depends on the fact that waves of different wavelengths may travel at different speeds (as might happen in shallow water), which prevents the waves from spreading out.

Also:

http://en.wikipedia.org/wiki/John_Scott_Russell
quote:

In 1834, while conducting experiments to determine the most efficient design for canal boats, he discovered a phenomenon that he described as the wave of translation. In fluid dynamics the wave is now called a Russell solitary wave or soliton. The discovery is described here in his own words:

"I was observing the motion of a boat which was rapidly drawn along a narrow channel by a pair of horses, when the boat suddenly stopped - not so the mass of water in the channel which it had put in motion; it accumulated round the prow of the vessel in a state of violent agitation, then suddenly leaving it behind, rolled forward with great velocity, assuming the form of a large solitary elevation, a rounded, smooth and well-defined heap of water, which continued its course along the channel apparently without change of form or diminution of speed. I followed it on horseback, and overtook it still rolling on at a rate of some eight or nine miles an hour, preserving its original figure some thirty feet long and a foot to a foot and a half in height. Its height gradually diminished, and after a chase of one or two miles I lost it in the windings of the channel. Such, in the month of August 1834, was my first chance interview with that singular and beautiful phenomenon which I have called the Wave of Translation".



Solitons exist otherwise than with tidal bores, but tidal bores are easier to imagine than quantum physics.