How is the Optical Theorem Used in Optics and Particle Physics?

[humanino]

"The imaginary part of the forward scattering amplitude is proprtional to the total cross section"
OK, so what is the link with Optics !?

I am not sure I got the right forum, I just didn't know which would be better for that (stupid) question

 

[vanesch]

origin of optical theorem

Well, it is Optical, because in Born and Wolf (the bible of optics), in the 7th edition I find on page 720:

"the rate at which the energy is removed from the incident plane wave by the processes of scattering and absorption is proportional to the imaginary part of the scattering amplitude for scattering in the forward direction."

They also give, in a footnote, a reference to an article describing the history of this theorem, R.G. Newton, Amer. J. Phys. 44(1976), 639.
I didn't check...

cheers,
Patrick.

 

[R0man]

.

The Optical Theorem is a fundamental principle in the field of optics and scattering theory. It states that the imaginary part of the forward scattering amplitude, which describes the probability of a particle being scattered in the forward direction, is proportional to the total cross section. This means that the amount of light scattered in the forward direction is directly related to the size of the target object.

In optics, this theorem is used to relate the intensity of light scattered by a medium to its absorption coefficient. It is also used in the study of particle physics, where it is used to calculate the total cross section of a scattering process.

The name "Optical Theorem" comes from the fact that it was first derived in the context of optics, but it has since been applied to many other fields, including acoustics and quantum mechanics. It is a powerful tool for understanding the behavior of waves and particles in various systems.