| Popis: |
We use the thermodynamic Bethe ansatz to find the finite-size corrections to the ground-state energy in an arbitrary (1 + 1)-dimensional purely elastic scattering theory. The leading finite-size effects are characterized by c = c − 12d 0 , where c and d 0 are the central charge and the lowest scaling dimension, respectively, of the (possibly nonunitary) CFT describing the ultraviolet limit of the massive scattering theory. After presenting the purely elastic S -matrix theories that emerged in recent discussions of perturbed CFTs, we calculate their finite-size scaling coefficient c . Our results show that the UV limits of the “minimal” S -matrix theories are the unperturbed CFTs in question. On the other hand, the S -matrices which have been suggested to describe affine Toda field theories, differing from the minimal S -matrices by coupling-dependent factors, are seen to have free bosonic CFTs as their UV limits. We also discuss some interesting properties of c . In particular, we suggest that c is a measure of the number of degrees of freedom of an arbitrary two-dimensional CFT. |
