Relativistic particle interactions - a comparison of independent and collective variable models

Abstract

We present a detailed comparison of two models for relativistic classical particle interactions recently discussed in the literature-one based on independent particle variables, and the other on centre of mass plus relative variables. Basic to a meaningful comparison is a reformulation of the latter model which shows that it makes essential use of the concept of invariant relations from constrained Hamiltonian theory. We conclude that these two models have, very different physical and formal structures and cannot be thought of as two equivalent descriptions of the same physical theory.