Quantum Field Theory and the Standard Model by Schwartz M.D. z-lib.org · Problem 8.1

Spin 1 and gauge invariance — Schwartz M.D. z-lib.org

Physics — QFT · probability-interpretation-norm-states

Problem

Show that having a probability interpretation, with

0 \leq \mathcal{P} \leq 1

, requires us to have only positive (or only negative) norm states.