On group averaging for non-compact groups

Abstract

We review some aspects of the use of a technique known as group averaging, which provides a tool for the study of constrained systems. We focus our attention on the case where the gauge group is non-compact, and a `renormalized' group averaging method must be introduced. We discuss the connection between superselection sectors and the rate of divergence of the group averaging integral.

5 pages, for the proceedings of the 9th Marcel Grossmann Conference, Rome 2000