We present a renormalization group analysis of a two dimensional Coulomb gas with internal degrees of freedom. The specific model considered has a global O(3) internal symmetry. The behavior of this system in the low temperature region is found to differ appreciably from that of the XY model. © 1981.

We show that vortex configurations generate a mass gap (finite correlation length) for T > 0 in non-abelian chiral SU(N) ×SU(N) spin systems in two dimensions. These vortices and the fluctuations around them mutually stabilize each other in the infrared. © 1980 North-Holland Publishing Company. All Rights Reserved.