We show how the spectral flow between the Neveu-Schwarz and Ramond sec
tors of N = 2 superconformal field theories can be described in three
dimensions in terms of the propagation of charged particles coupled to
a Chern-Simons gauge theory. Quantum mechanical mixing between the de
generate Chem-Simons vacua interpolates between the different boundary
conditions of the two sectors and so provides a dynamical picture for
the GSO projection. (C) 1997 Elsevier Science B.V.