Center vortex model for the infrared sector of Yang-Mills theory - Confinement and Deconfinement

A model for the infrared sector of Yang-Mills theory based on magnetic vortices represented by (closed) random surfaces is investigated using lattice Monte Carlo methods. The random surfaces are governed by a surface area action and a curvature action. The model generates a finite-temperature deconfinement transition; the coupling constants of the model can be chosen such as to reproduce the SU(2) Yang-Mills ratio of the deconfinement temperature to the square root of the zero-temperature string tension, T_c / sqrt{sigma_0} =0.69. This yields a physical trajectory in the space of coupling constants on which the confinement properties are approximately invariant. An at first sight surprisingly accurate prediction of the spatial string tension in the deconfined phase results, which can be made plausible in view of the specific space-time structure of the vortex configurations in this phase. The confinement properties are shown to be intimately tied to the percolation properties of the vortex surfaces.