Collective variables in elementary quantum mechanics: Eugene P.Gross
In the present article I discuss some features of the use of collective coordinates in two systems with a small number of degrees of freedom. In both cases the utility of collective coordinates is connected with the validity of an adiabatic approximation. The two examples are pedagogical in nature, but are perhaps appropriate in a volume honoring David Bohm, who has made major contributions to the theory of collective coordinates. First, however, I present some personal reminiscences of the days when I was a student of David Bohm.