Fig. 6: Evidence for the first-order phase transition.

The figure shows the coefficient of the anisotropy ν4 in the effective action (4) as function of V, which is computed from the QMC histogram data of the O(3) order parameter in Fig. 3. ν4 changes sign at the LN–VP transition, signifying the change from face- to corner-cubic anisotropy in the effective action of the lattice model. The error bars here represent the standard error of the mean, which is calculated as \(\sigma /\sqrt{N}\), where σ is one standard deviation and N is the total number of independent samples.