Center Vortex Model for the Infrared Sector of SU(3) Yang-Mills Theory

The vortex picture of the Yang-Mills vacuum, initially proposed as a possible mechanism of colour confinement, has recently attracted a renewed attention. This is mainly due to the advent of new gauge fixing techniques which permit the detection of center vortex structures directly within lattice Yang-Mills configurations. Numerical studies have revealed that the center projection vortices detected in this way do locate true physical objects (rather than lattice artifacts) [1], and there is by now ample evidence that the infrared properties of Yang-Mills theory can be accounted for in terms of vortices [2]. Based on these ideas, a random vortex world-surface model was introduced as an effective low-energy description of SU(2) Yang-Mills theory [3]; it has recently been extended to the gauge group SU(3) [4]. The fundamental assumption is that the longrange structure of Yang-Mills theory is dominated by extended tubes of center flux tracing out closed surfaces in space-time. Consequently, we realise our model on a spacetime lattice in which the fixed spacing a represents the transverse thickness of vortices. The random surfaces created on this lattice are weighted by a model action containing a Nambu-Goto and a curvature term, with dimensionless coupling constants ε and c, respectively. Physically, this means that vortices have a certain surface tension and they tend to be stiff. For further details on our model and the determination of the parameters ε and c (as well as the vortex extension a = 0.39fm), the reader is referred to [4].