Wigner Representation Theory of the Poincaré Group, Localization , Statistics and the S-Matrix

It has been known that the Wigner representation theory for positive energy orbits permits a useful localization concept in terms of certain lattices of real subspaces of the complex Hilbert -space. This ”modular localization” is not only useful in order to construct interactionfree nets of local algebras without using non-unique ”free field coordinates”, but also permits the study of properties of localization and braid-group statistics in low-dimensional QFT. It also sheds some light on the string-like localization properties of the 1939 Wigner’s ”continuous spin” representations.We formulate a constructive nonperturbative program to introduce interactions into such an approach based on the Tomita-Takesaki modular theory. The new aspect is the deep relation of the latter with the scattering operator.