Lattice study of 3D compact QED at finite temperature

We study the deconfinement phase transition and monopole properties in a finite temperature three-dimensional compact Abelian gauge model on the lattice. We predict the critical coupling as a function of the lattice size in a simplified model to describe monopole binding. We demonstrate numerically that monopoles are sensitive to the transition. In the deconfinement phase the monopoles appear in the form of a dilute gas of magnetic dipoles. In the confinement phase both monopole density and string tension differ from semiclassical estimates if monopole binding is neglected. However, an analysis of the monopole clusters shows that the relation between the string tension and the density of monopoles in charged clusters is in reasonable agreement with predictions. We study the cluster structure of the vacuum in both phases of the model.