There is no roughening singularity at finite temperature

It is shown, for any non-zero temperature and finite coupling, that there are large transverse fluctuations in the electric flux tubes connecting quark-antiquark pairs. For large qanti q separation L, the average distance of the flux tube from its equilibrium position diverges like √L. Hence the flux tube is rough. The consequent absence of a roughening singularity may imply that rotational invariance and the continuum limit are approached more gradually than at zero temperature. (orig.)