↧
Answer by AccidentalFourierTransform for Why does the QCD vacuum have zero...
@ACuriousMind 's answer is pretty straightforward. As an alternate proof consider the following:Note that $\hat P^\mu$ is time-independent$^1$, which means that it commutes with $\hat H$. So it...
View ArticleAnswer by ACuriousMind for Why does the QCD vacuum have zero momentum?
It's by definition. A vacuum state is defined to be Poincaré invariant, since it should not depend on the frame (in special relativistic QFT; you get frame-dependent vacua in QFT in curved...
View ArticleWhy does the QCD vacuum have zero momentum?
Today in the hadron physics tutorial we were talking about the Fabri-Picasso theorem where one step in the proof involves $\hat P |0\rangle$ which is the four-momentum operator on the vacuum. And from...
View Article