Deconfinement in the two-dimensional XY model.
The unbinding of vortex-antivortex pairs for the classical two-dimensional XY model in a magnetic field is studied. A single such pair is connected by a string of overturned spins, leading to linear confinement. We show that this system supports two phase transitions, one in which closed strings proliferate, and a second in which vortices unbind. The transitions are shown to be dual to one another, and are remarkably continuous. Possible consequences for a variety of systems are discussed.
Fertig
H A
HA
Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055, USA.