Stability and collapse of a coupled Bose-Einstein condensate

The dynamics of a coupled Bose-Einstein condensate involving trapped atoms in two quantum states is studied using the time-dependent Gross-Pitaevskii equation including an interaction which can transform atoms from one state to the other. We find interesting oscillation of the number of atoms in eac h of the states. For all repulsive interactions, stable condensates are for med. When some of the atomic interactions are attractive, the possibility o f collapse is studied by including an absorptive contact interaction and a quartic three-body recombination term. One or both components of the conden sate may undergo collapse when one or more of the nonlinear terms are attra ctive in nature. (C) 2001 Elsevier Science B.V. All rights reserved.