Numerical minimization of the Euclidean action of the two-dimensional Abelian
Higgs model is used to construct periodic instantons, the euclidean field
configurations with two turning points describing transitions between the
vicinities of topologically distinct vacua. Periodic instantons are found at
any energy ( up to the sphaleron energy Esph ) and for wide range of
parameters of the theory. We obtain the dependence of the action and the energy
of periodic instanton on its period; these quantities directly determine the
probability of certain multiparticle scattering events.Comment: 8 pages, 6 figures available upon request, LaTeX, ITP-SB-92-7