O(5) multicriticality in the three-dimensional two-flavor SU(2) lattice gauge Higgs model

We numerically investigate the multicritical behavior of the three-dimensional lattice system in which a SU(2) gauge field is coupled to two flavors of scalar fields transforming in the fundamental representation of the gauge group. In this system, a multicritical point is present, where the global symmetry O(2)⊕O(3) gets enlarged to O(5). Such a symmetry enlargement is hindered for generic systems by the instability of the O(5) multicritical point, but the SU(2) gauge symmetry prevents the appearance of the term triggering the instability. All the numerical results obtained in this lattice gauge model fully support the expectations coming from the O(2)⊕O(3) multicritical Landau-Ginzburg-Wilson φ4 theory, and we discuss possible implications of these results for some models of deconfined quantum criticality.