  This is a new version of the paper, which uses the same methods as in the
previous version, but the model is now different. We study two complex scalar
fields coupled through a quadratic interaction in 2+1 dimensions. We use the
method of bilinears as suggested by Rajeev. The resulting classical theory is
studied within the linear approximation and we show that there is a possible
bound state for the composite type particles for a range of coupling constant
strengths.
