Phase transitions not controlled by stable fixed points

Abstract
A free-energy functional which describes two possible phase transitions in superfluid 3He is investigated with renormalization group techniques. The phase transitions are found not to be controlled by stable fixed points, at least within an in expansion. 1/n calculations suggest that in this instance the transitions are first order. An 'improved' one-loop calculation of the free energy is given to illustrate the difficulties of calculating the free energy in a systematic manner in the absence of control by stable fixed points.