Relativistic Invariance and the Spectral Decomposition of G ⁽²⁾

Abstract

The requirements for a relativistically invariant quantum field theory. Generators of the unitary representations of the universal covering group of the Poincaré group, and their commutation relations. The spectral decomposition of the two-point function G ⁽²⁾ in the quantum theory of the real scalar field. The contribution of the single particle states. The pole of ˜G ⁽²⁾ at the physical value of p ² of the single particle. Finite mass corrections to the renormalized two-point function.