Conformal anomaly and critical exponents of the spin-1 Takhtajan-Babujian model

The authors consider the critical behaviour of the spin-1 Hamiltonian of the Takhtajan-Babujian model. The Bethe ansatz equations for this antiferromagnet in a finite chain are investigated analytically and numerically. The conformal anomaly and critical exponents are obtained by exploiting their relations with the eigenspectrum of the finite system. The results strongly support the conjecture that the Wess-Zumino-Witten non-linear sigma model with topological charge k=2 is the underlying field theory for this statistical mechanics model.