The formation and evolution of U(1) gauged vortices in an expanding universe

The formation and evolution of gauged U(1) vortices in an expanding (2+1)-dimensional space-time are analyzed numerically. We find that, starting with thermal initial conditions with random phases, vortices form with a mean separation smaller than the Hubble radius. Thus the Kibble mechanism holds also in local gauge theories. In contrast to the case of global vortices, there are no long-range forces. However, for certain initial conditions, vortex may collide with an antivortex. In this case, they annihilate in a spiral path evident angular momentum. We show that the phase waves which are produced during the annihilation are emitted predominantly at 90deg from the axis through the incident topological defects. (orig.)