The phase transition in the continuous Potts model

Abstract
The Callan-Symanzik technique is applied to the continuous Potts model. It is shown that close to four dimensions the phase transition can be continuous if and only if the bare coupling of the cubic term, phi 13-3 phi 1 phi 22, vanishes, as predicted by the Landau criterion. This is shown to be the result of the fact that the fixed point of the renormalized cubic coupling constant is at zero and is ultraviolet-stable.