2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/179389This 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.12 pages, to appear in JMPHigh Energy Physics - Theorytext