Dynamical Critical Exponent for Two-Species Totally Asymmetric Diffusion on a Ring

We present a study of the two species totally asymmetric diffusion model using the Bethe ansatz. The Hamiltonian has U_q(SU(3)) symmetry. We derive the nested Bethe ansatz equations and obtain the dynamical critical exponent from the finite-size scaling properties of the eigenvalue with the smallest real part. The dynamical critical exponent is 3/2 which is the exponent corresponding to KPZ growth in the single species asymmetric diffusion model.