Register to reply

Fine structure constant and perturbation theory...

by asimov42
Tags: constant, fine, perturbation, structure, theory
Share this thread:
asimov42
#1
Apr24-12, 12:51 AM
P: 51
Hi all,

I have a question about perturbation theory and the fine structure constant. Consider an electron moving through the vacuum - this wil induce vacuum polarization, and (if I understand correctly) perturbation theory can be used to analyze the situation. My question is essentially: if the fine structure constant took on a different value (as some theories predict is can), would the interaction between the electron field and the electromagnetic field be different? That is, would you draw a different sequence of Feynman diagrams for the different cases (alpha_1 vs. alpha_2) - does changing the strength of the electromagnetic interaction change the perturbative (or non-perturbative) result?

Thanks!
Phys.Org News Partner Physics news on Phys.org
Engineers develop new sensor to detect tiny individual nanoparticles
Tiny particles have big potential in debate over nuclear proliferation
Ray tracing and beyond
mfb
#2
Apr24-12, 08:56 AM
Mentor
P: 11,925
You would draw the same sets of diagrams, but their relative strength (at different orders of alpha) would vary. With a smaller alpha, higher orders would have less influence, and with a large alpha, a lot of different diagrams would contribute significantly.

You can see this at the strong force: It has a large coupling constant, and perturbative calculations are much more difficult there.


Register to reply

Related Discussions
Fine structure constant Quantum Physics 3
Grand Unification Theory fine structure constant... High Energy, Nuclear, Particle Physics 5
The Fine Structure Constant Quantum Physics 3
Fine Structure Constant Astronomy & Astrophysics 3
Is Boltzman's Constant related to the Fine Structure Constant? Quantum Physics 6