Determination of Invariant Amplitudes from Experimental Observables
Michael J. Moravcsik, Wing-Yin Yu · Journal of Mathematical Physics · 1969
Necessary and sufficient conditions are formulated for deciding whether a set of 2n − 1 bilinear products of n complex amplitudes determines these amplitudes with no continuum of ambiguity or not. The conditions can be translated into very simple geometrical prescriptions which in most cases provide quick and easy practical tests for such decisions.