Topological defect brane-world models

Abstract

5-dimensional homogeneous and isotropic models with a bulk cosmological constant and a minimally coupled scalar field are considered. We have found that in special cases the scalar field can mimic a frustrated (i.e. disordered) networks of topological defects: cosmic strings, domain walls and hyperdomain walls. This equivalence enabled us to obtain 5-dimensional instantonic solutions which can be used to construct brane-world models. In some cases, their analytic continuation to a Lorentzian metric signature give rise to either 4-dimensional flat or inflating branes. Models with arbitrary dimensions (D $>$ 5) are also briefly discussed.