Non-relativistic bound states: the long way back from the Bethe-Salpeter to the Schroedinger equation

Abstract

I review, in a personal perspective, the history of the theory of non-relativistic bound states in QED and QCD from the Bethe-Salpeter equation to the construction of effective field theories.

Comments: Contribution to "Fundamental Interactions - A Memorial Volume for Wolfgang Kummer", D. Grumiller, A. Rebhan, D.V. Vassilevich (eds.); 17 pages, 6 figures; references added