Zero modes in nonlocal domain walls

We generalize the Callan–Harvey mechanism to the case of actions with a nonlocal mass term for the fermions. Using a (2+1)-dimensional model as a concrete example, we show that both the existence and properties of localized zero modes can also be consistently studied when the mass is nonlocal. We derive some general properties from a study of the resulting integral equations, and consider their realization in a concrete example.