# The G-factor?

1. Dec 6, 2012

### JJHK

Hello, I'm having a hard time grasping this g-factor. Why was it invented? How do you solve for it?

I'm currently using Serway's Modern Physics textbook right now, and I feel like it skimped on it so much that I just have no idea what it really is. If someone can expound, it would be greatly appreciated!

2. Dec 7, 2012

### tom.stoer

The g-factor follows from a relativistic effect which can be derived naturally from the Dirac equation

3. Dec 7, 2012

### dextercioby

IIRC, g=2 for electron can be derived from Galilean-invariant quantum dynamics. The work by J.M. Lévy-Leblond supports this claim.

Last edited: Dec 7, 2012
4. Dec 7, 2012

### andrien

are you talking about lande factor? Yes,it can be derived naturally from Dirac eqn for electron.Also g is not exactly 2 because of radiative corrections.(vertex correction)

5. Dec 8, 2012

### Meir Achuz

There is a simple formula relating the magnetic moment to the angular momentum J
in many simple cases:
$$\mu=(e/2mc)J$$.
When this relation is different a dimensionless factor g is introduced as
$$\mu=g(e/2mc)J$$.
For the electron the g factor is ver close to g=2.