We review the status of domain walls in N = 1 supergravity theories for both the vacuum domain walls as well as dilatonic domain walls. We concentrate on a systematic analysis of the nature of the space–time in such domain wall backgrounds and the special rôle that supersymmetry is playing in determining the nature of such configurations. Isotropic vacuum domain walls that can exist between iso...

QCD was shown to have a nontrivial vacuum structure due to the topology of the θ ≡ θ+2πn parameter. As a result of this nontrivial topology, in the large Nc limit, quasi-stable QCD domain walls appear, characterized by a transition in the singlet η field. We discuss the physics of these QCD domain walls as well as related axion domain walls and we present a new type of axion wall which also con...

We explore the stability of domain wall and bubble solutions in theories with compact extra dimensions. The energy density stored inside of the wall can destabilize the volume modulus of a compactification, leading to solutions containing either a timelike singularity or a region where space decompactifies, depending on the metric ansatz. We determine the structure of such solutions both analyt...

We find an anisotropic, non-supersymmetric generalization of the extreme supersymmetric domain walls of simple non-dilatonic supergravity theory. As opposed to the isotropic nonand ultra-extreme domain walls, the anisotropic non-extreme wall has the same spatial topology as the extreme wall. The solution has naked singularities which vanish in the extreme limit. Since the Hawking temperature on...