DOMAIN-WALLS AND PERTURBATION-THEORY IN HIGH-TEMPERATURE GAUGE-THEORY- SU(2) IN 2+1 DIMENSIONS

We study the detailed properties of Z(2) domain walls in the deconfine d high-temperature phase of the d=2+1 SU(2) gauge theory. These walls are studied both by computer simulations of the lattice theory and by one-loop perturbative calculations. The latter are carried out both in the continuum and on the lattice. We find that leading order perturba tion theory reproduces the detailed properties of these domain walls r emarkably accurately even at temperatures where the effective dimensio nless expansion parameter g(2)/T is close to unity. The quantities stu died include the surface tension, the action density profiles, roughen ing, and the electric screening mass. It is only for the last quantity that we find an exception to the precocious success of perturbation t heory. All this shows that, despite the presence of infrared divergenc es at higher orders, high-T perturbation theory can be an accurate cal culational tool.