ON U(Q)[SU(2)]-SYMMETRICAL DRIVEN DIFFUSION

We study analytically a model where particles with hard-core repulsion diffuse on a finite one-dimensional lattice with space-dependent, asymmetric hopping rates. The dynamics are given by the U(q)[SU(2)]-symmetric Hamiltonian of a generalized anisotropic Heisenberg ferromagnet. Exploiting this symmetry, we derive exact expressions for various correlation functions. In the weakly driven system correlation length xi(s) and correlation time xi(t) are related by xi(t) - xi(s)2 indicating a dynamical exponent z = 2 as for symmetric diffusion. But also in strongly driven systems with finite density we find correlation functions with a dynamical exponent z = 2. This is not expected from the finite-size scaling analysis of the model.