Cosmic strings in Bekenstein-type models

Abstract

We study static cosmic string solutions in the context of Bekenstein-type models. We showthat there is a class of models of this type for which the classical Nielsen–Olesen vortex isstill a valid solution. However, in general, static string solutions in Bekenstein-type modelsstrongly depart from the standard Nielsen–Olesen solution with the electromagnetic energyconcentrated along the string core seeding spatial variations of the fine structure constant,α. We consider models with a generic gauge kinetic function and show that theequivalence principle constraints impose tight limits on the allowed variations ofα induced by string networks on cosmological scales.