- #1
center o bass
- 560
- 2
Hi! I'm used to integrating over infinite spaces when working with QFT so far, but in an exercise I stumbled across a statement that
[tex] \int_V d^3x e^{-i \vec x \cdot (\vec p - \vec p')} = V \delta_{\vec p \vec p'} [/tex]
It is clear that this is okay when p = p', but it does not seem to make sense when this is not the case. I would however agree that it's approximately true when V is large. Is this what is meant by this statement? Is it a large V approximation?
[tex] \int_V d^3x e^{-i \vec x \cdot (\vec p - \vec p')} = V \delta_{\vec p \vec p'} [/tex]
It is clear that this is okay when p = p', but it does not seem to make sense when this is not the case. I would however agree that it's approximately true when V is large. Is this what is meant by this statement? Is it a large V approximation?