Exploiting duality in a toy model of QCD at non-zero temperature and   chemical potential: the massive Thirring model, sine-Gordon model and Coulomb   gases
  We focus on the massive Thirring model in 1+1 dimensions at finite temperature and non-zero chemical potential, and comment on some parallels between this model and QCD. In QCD, calculations of physical quantities such as transport coefficients are extremely difficult. In the massive Thirring model, similar calculations are greatly simplified by exploiting the duality which exists with the sine-Gordon model and its relation, at high temperature, to the exactly solvable classical Coulomb gas on the line. 
D. A. Steer, A. Gomez Nicola, R. J. Rivers and T. S. Evans