TRUNCATED CONFORMAL SPACE AT C=1, NONLINEAR INTEGRAL-EQUATION AND QUANTIZATION RULES FOR MULTISOLITON STATES

We develop truncated conformal space (TCS) technique for perturbations of c = 1 conformal field theories. We use it to give the first numeri cal evidence of the validity of the non-linear integral equation (NLIE ) derived from light-cone lattice regularization at intermediate scale s. A controversy on the quantization of Bethe states is solved by this numerical comparison and by using the locality principle at the ultra violet fu;ed point. It turns out that the correct quantization for pur e hole states is the one with half-integer quantum numbers originally proposed by Fioravanti et al. [Phys. Lett. B 390 (1997) 243]. Once the correct rule is imposed, the agreement between TCS and NLIE for pure hole states turns out to be impressive. (C) 1998 Elsevier Science B.V. All rights reserved.