DOMAIN-WALLS IN STRONGLY COUPLED THEORIES

Domain walls in strongly coupled gauge theories are discussed. A gener al mechanism is suggested automatically leading to massless gauge boso ns localized on the wall. In one of the models considered, outside the wall the theory is in the non-Abelian confining phase, while inside t he wall it is in the Abelian Coulomb phase, The confining property of the non-Abelian theories is a key ingredient of the mechanism which ma y be of practical use in the context of the dynamic compactification s cenarios. In supersymmetric (N = 1) Yang-Mills theories the energy den sity of the wall can be exactly calculated in the strong coupling regi me, This calculation presents a further example of non-trivial physica l quantities that can be found exactly by exploiting specific properti es of supersymmetry. A key observation is the fact that the wall in th is theory is a BPS-saturated state. (C) 1997 Published by Elsevier Sci ence B.V.