- #1
Sleuth
- 47
- 4
Hi everybody,
I don't know if this is the right section to ask for such a question but I have been dealing with this problem for a while and there's something I still cannot grasp...
Let us suppose that we have a dirac free particle with propagator (i'm sorry but I'm not able to obtain the feynman slash notation in TeX)
suppose [tex] p = (p_0, P)[/tex]
[tex] {i \over p/ - m} = i {p_0 \gamma_0 - P \cdot \gamma + m \over p_0^2 - P^2 -m^2} [/tex]
My question is how can I perform a non relativistic expansion and recover the non relativistic propagator
[tex] {1 \over E - {P^2 \over 2 m}} [/tex]
with E as the kinetic energy?
I have a couple of ideas quite long to write down, but I cannot justify them completely so I'd accept some hint gladly :)
I don't know if this is the right section to ask for such a question but I have been dealing with this problem for a while and there's something I still cannot grasp...
Let us suppose that we have a dirac free particle with propagator (i'm sorry but I'm not able to obtain the feynman slash notation in TeX)
suppose [tex] p = (p_0, P)[/tex]
[tex] {i \over p/ - m} = i {p_0 \gamma_0 - P \cdot \gamma + m \over p_0^2 - P^2 -m^2} [/tex]
My question is how can I perform a non relativistic expansion and recover the non relativistic propagator
[tex] {1 \over E - {P^2 \over 2 m}} [/tex]
with E as the kinetic energy?
I have a couple of ideas quite long to write down, but I cannot justify them completely so I'd accept some hint gladly :)