Register to reply

Probability a photon will couple with an electron

by Epistimonas
Tags: couple, electron, photon, probability
Share this thread:
Jan11-11, 10:48 PM
P: 11
Hello, I am new to these forums and this is my first post.

Anyways, I am trying to come up with a formula of the probability amplitude of an electron-photon coupling; more specifically, a photon colliding with an electron. I used Q.E.D. by Richard Feynman as a basis for the formula, using the simplistic Feynman diagrams and the basic formulas he describes.

The formula is based on an electron starting at an arbitrary point, 1, moving through space-time to an arbitrary point, 2, coupling with a photon, then continuing off in another direction to an arbitrary point 3. Feynman made it sound ridiculously easy to calculate probability amplitudes for such events, however, he used an imaginary spin-0 electron to simplify it. A real electron obviously takes every path connecting the two points and the probability amplitude that it will go from point 1 to 2 is:

E(1 to 2) = P(1 to 2) + P(1 to 3)*n^2*P(3 to 2) + P(1 to 4)*n^2*P(4 to 5)*n^2*P(5 to 2) + .... for all intermediate points

Where n is a number that makes the calculation agree with experiment and is the amplitude for each stop.

Can someone explain the basics of how I would write a formula that includes all intermediate terms? What would they be? When would they stop? Would it have to be represented by a definite integral with an upper limit of infinity?
Phys.Org News Partner Physics news on
Step lightly: All-optical transistor triggered by single photon promises advances in quantum applications
The unifying framework of symmetry reveals properties of a broad range of physical systems
What time is it in the universe?

Register to reply

Related Discussions
Photon absorption and probability of atomic electron transition Quantum Physics 3
A couple probability questions Set Theory, Logic, Probability, Statistics 2
Electron VS. photon Quantum Physics 32
A Couple of Probability & Statistics Questions Precalculus Mathematics Homework 5
Can photon couple to scalar field? High Energy, Nuclear, Particle Physics 7