Numerical Study of Periodic Instanton Configurations in Two-dimensional Abelian Higgs Theory

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 $E_{sph}$ ) 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