The flux-tube phase transition
  We consider the phase transition in the "hot" dual long-distances Yang-Mills theory at finite temperature $T$. This phase transition is associated with a change of symmetry. The dual model is formulated in terms of two-point Wightman functions with equations of motion involving higher derivatives. The effective mass of the dual gauge field is derived as a function of $T$-dependent gauge coupling constant. 
G.A. Kozlov and G. Khoriauli