Finding topological solitary waves in models with non-equivalent vacua

We study the existence of bidimensional bosonic models for which the sponta neous symmetry breaking phenomenon yields, at classical level, non-equivale nt vacua. Once we introduce the concept of vacuum manifold V, defined in te rms of the vacuum field configurations, the behavior of the models at issue can be analyzed by means of the so-called classical moduli space M-c(V). T he aforementioned structure allows us to classify the kink-like excitations into loops and links. To be precise, the loops interpolate smoothly betwee n equivalent minima of the classical potential while the links connect vacu a located at different points in M-c(V). Although exact results are very ha rd to come by, we resort to models simple enough to provide us with the sol itary waves in closed form. (C) 2000 Elsevier Science Ltd. All rights reser ved.