The Width of the Colour Flux Tube
  We discuss and rederive in a general way the logarithmic growth of the mean squared width of the colour flux tube as a function of the interquark separation. Recent data on 3D $Z_2$ gauge theory, combined with high precision data on the interface physics of the 3D Ising model fit nicely this behaviour over a range of more than two orders of magnitude. 
M. Caselle, F. Gliozzi, U. Magnea and S. Vinti