BOUNDARY CRITICAL PHENOMENA IN THE 3-STATE POTTS-MODEL

Boundary critical phenomena are studied in the three-state Potts model in two dimensions using conformal field theory, duality and renormali zation group methods. A presumably complete set of boundary conditions is obtained using both fusion and orbifold methods. Besides the previ ously known free, fixed and mixed boundary conditions a new one is obt ained. This illustrates the necessity of considering fusion with opera tors that do not occur in the bulk spectrum, to obtain all boundary co nditions. It is shown that this new boundary condition is dual to the mixed ones. The phase diagram for the quantum chain version of the Pot ts model is analysed using duality and renormalization group arguments .