Lattice Evidence for Gauge Field Localization on a Brane

We examine the problem of gauge-field localization in higher-dimensional gauge theories. In particular, we study a five-dimensional U(1) by lattice techniques and we find that gauge fields can indeed be localized. Two models are considered. The first one has anisotropic couplings independent of each other and of the coordinates. It can be realized on a homogeneous but anisotropic flat Euclidean space. The second model has couplings depending on the extra transverse fifth direction. This model can be realized by a U(1) gauge theory on the Randall-Sundrum background. We find that in both models a new phase exists, the layer phase, in which a massless photon is localized on the four-dimensional layers. We find that this phase is separated from the strong coupling phase by a second order phase transition.