# State optical theorem

##### *2019-11-22 02:27*

short: The optical theorem follows directly from the unitarity of the Smatrix. How can we dene the Smatrix in a physical meaningful way? Lets take a look at this Michael Ronniger The Optical Theorem and Partial Wave UnitarityHow can the answer be improved? state optical theorem

in \phi4 theory, using the optical theorem, and I'm having trouble. All of the examples I can find use the theorem to relate the imaginary part of the total 2particle to 2particle forward scattering amplitude to the total crosssection; that's not what I'm trying to do.

View Homework Help Homework on Born Approximation And The Optical Theorem from PHY 7410 at Wayne State University. PHY7410. Homework 5 This homework assignment is due on March 5 Optical theorem. In physics, the optical theorem is a general law of wave scattering theory, which relates the forward scattering amplitude to the total cross section of the scatterer. It is usually written in the form where f (0) is the scattering amplitude with an angle of**state optical theorem** The optical theorem \sigmatot \frac4\pik \textIm(f(0)) links the total cross section with the imaginary part of the scattering amplitude. My lecture notes say that this is a Stack Exchange Network

Equation (22) is the optical theorem; it relates the extinc tion cross section to the imaginary part of the scattering amplitude evaluated in the forward direction. *state optical theorem* CURRENTS AND OPTICAL THEOREM February 11, 2015 Lecture IX 1. 2 Currents and optical theorem 0 s (1. 1) 0represents the incoming free particle and is a solution to H0 0 i @ @t 0 where H 0 p2 2m. Then H i @ @t where H H0 V and state, where there is some zaxis de ned by something. The nal state has the same angular Physics 216 Spring 2012. TheOptical Theorem. 1. The probability currents In the quantum theory of scattering, the optical theorem is a consequence of the conser vation of probability. As usual, we dene (x, t) (x, t)2, j(x, t) i 2m h (x, t)(x, t) (x, t)(x, t) i. Last time we mentioned scattering removes power from beam. I the optical theorem: I the relationship of the index of refraction and the forward scattering amplitude. The optical theorem relates the total cross section to the forward scattering amplitude. In Quantum Mechanics, this is conservation of probability. 1. 2 Optical Theorem Constraint The optical theorem places important constraints on f l. Recall the optical theorem Z df2 4 k f(0). (5) The l. h. s. is Z df2 2 Z dcos X l, l0 (2l1)(2l0 1)f lf l0 P l(cos)P l0(cos) 4 X l (2l1)f l2. (6) Here, normalization and orthogonality of the Legendre polynomials Z 1 1 P l(t)P l 0(t)dt 2 2l1 l, l (7) was used.