Transitions between Hall plateaux and the dimerization transition of a Hubbard chain

We show that the plateau transitions in the quantum Hall effect are the same as the dimerization transition of a half-filled one-dimensional U(2n) Hubbard model at n=0. We address the properties of the latter by a combination of perturbative renormalization group and Monte Carlo simulations. Results on both critical and o-critical properties are presented.