Warped domain wall fermions

We consider Kaplan's domain wall fermions in the presence of an Anti-deSitter (AdS) background in the extra dimension. Just as in the flat space case,in a completely vector-like gauge theory defined after discretizing this extradimension, the spectrum contains a very light charged fermion whose chiralcomponents are localized at the ends of the extra dimensional interval. Thecomponent on the IR boundary of the AdS space can be given a large mass bycoupling it to a neutral fermion via the Higgs mechanism. In this theory, gaugeinvariance can be restored either by taking the limit of infinite proper lengthof the extra dimension or by reducing the AdS curvature radius towards zero. Inthe latter case, the Kaluza-Klein modes stay heavy and the resulting classicaltheory approaches a chiral gauge theory, as we verify numerically. Potentialdifficulties for this approach could arise from the coupling of thelongitudinal mode of the light gauge boson, which has to be treatednon-perturbatively