Jun yan , Bao-Lin Li, “Functional integrals and convergence of partition function in Sine-Gordon-Thirring Model”, The effective action in 1D sine-Gordon-Thirring model with impurities coupling
is derived by means of functional integral method. For strong coupling model, the convergence of partition function is proved when coupling constants and wave vector satisfy certain constraint conditions. The fermion condense density in stable phase structure is obtained from the extremum of two-order effective action., LETTERS IN MATHEMATICAL PHYSICS, 104:2 (2014), 233-242