CONFORMAL SPECTRUM OF THE 6-VERTEX MODEL

By way of a generalization of analytical methods recently introduced, the conformal spectrum of the six-vertex model with twisted boundary conditions is analysed. Nonlinear integral equations are derived, from which all scaling dimensions x and the spins s can be extracted analytically in terms of Rogers dilogarithms. For twist angle phi, the scaling dimensions of low-lying excitations are given by the so-called Gaussian dimensions x=1-gamma/pi/2S2+1/2(1-gamma/pi)(m-phi/pi)2 where gamma is the crossing parameter, S the magnetization and m another integer characterizing the excited state. These results are applied to the calculation of critical exponents of the eight-vertex model. Further applications are pointed out.