Kink dynamics under odd perturbations for (1+1)-scalar field models with one internal mode

Abstract

We consider odd symmetric (1+1)-scalar field models with one internal mode. Under natural and robust assumptions, including the Fermi golden rule, we prove the asymptotic stability of the kink by odd perturbations in the energy space. For example, the result applies to the ${\varphi }^4$ model with odd symmetry and some of its perturbations.