  We propose a new approach to the macroscopic dynamics of three-well
Bose-Einstein condensates, giving particular emphasis to self-trapping and
Josephson oscillations. Although these effects have been studied quite
thoroughly in the mean-field approximation, a full quantum description is
desirable, since it avoids pathologies due to the nonlinear character of the
mean-field equations. Using superpositions of quantum eigenstates, we construct
various oscillation and trapping scenarios.
