Two-component radial quartic Landau potential ($g({\varphi }_1^2+{\varphi }_2^2{)}^2$)

With positive $g$, the quadratic coefficients select the component with the smaller negative coefficient. Equal negative coefficients give a circle of minima in the mean-field approximation; the negative diagonal is a spin-flop transition, ending at a bicritical point at the origin.