New posts in S Matrix Theory

Why amplitudes are rational functions?

Why can we shift the field $\phi$, so that $\langle \Omega | \phi(x) | \Omega \rangle = 0$?

Contradiction between aymptotically free particles in QFT and unlocalization

What actually means to compute things at tree level?

Quantum Field Theory in position space instead of momentum space?

The contradiction between Gell-mann Low theorem and the identity of Møller operator $H\Omega_{+}=\Omega_{+}H_0$

What are the differences (if any) between the Dyson's series definition and the "in/out" definition of the $S$-matrix

Relation between Borchers class and the LSZ formula on S-matrix equivalence

Why does the action have to be hermitian?

Renormalization condition: why must be the residue of the propagator be 1?