Interface tension in the Polyakov loop model

The interface tension of the Polyakov loop model is calculated by Monte Carlo simulation. The form of the operator measuring the tension is derived from QCD in the strong coupling limit. The result is αa ³=0.0255±0.0003 in terms of the lattice constanta. The interface profile is also calculated and the spatial extent of the interface is estimated to be 10 lattice spacings. The result implies that the phase transition in the Polyakov loop model is of first order.