Comments on noncommutative gauge theories

We study the gauge theories on noncommutative space. We employ the idea of the covariant position to understand the linear and angular momenta, the center of mass position, and to express all gauge invariant observables including the Wilson line. In addition, we utilize the universality of the U(1) gauge theory, which originates from the underlying matrix theory, to analyze various solitons on U(N) theories, like the unstable static vortex solutions in two dimensions and BPS dyonic fluxon solutions. (C) 2001 Published by Elsevier Science B.V.