SINE–GORDON THEORY IN THE REPULSIVE REGIME, THERMODYNAMIC BETHE ANSATZ AND MINIMAL MODELS

Abstract

Neutral excitations present in the repulsive regime (1/2 < β2/8π < 1) of the sine–Gordon/massive–Thirring model and its study of the massless limit by the thermodynamic Bethe ansatz is revisited. At β2/8π = 1-1/(p+1) the solitons become infinitely heavy, forcing truncation to the neutral excitations alone. The central charge in this limit is calculated to be c = 1-6/p(p+1); the mass and S-matrices of the truncated theories are identified as those of the minimal conformal theory Mp perturbed by the ϕ(1, 3) operator.