  Effective action of center vortices in SU(2) lattice gauge theory is
investigated by studying the correlation between the action density on their
worldsheets and their geometric properties. It turns out that center vortices
are rigid, however, their dynamics is more complicated than that of rigid
random surfaces, since some coupling constants have nonstandard scaling
dimensions. As a result, the properties of center vortices are almost
completely determined by curvature-dependent effects. This, in turn, provides a
qualitative explanation of vortex percolation.
