Speaker
Description
We conduct numerical simulations to map out the phase diagram and critical behavior of a lattice Higgs model composed of a massless staggered fermion transforming in the fundamental representation of $SU(2)$ and coupled to a scalar field in the adjoint representation of the group. The scalar action consists of quadratic, quartic terms and a derivative term. At fixed quartic coupling we explore a two dimensional parameter space finding a massless symmetric phase at weak coupling and a massive symmetric phase (SMG phase) at strong coupling. An intermediate anti-ferromagnetic phase separates these two regimes. These results are consistent with leading order weak and strong coupling expansions. However we find that the critical lines bounding the intermediate phase merge at a unique point where all fermion bilinear condensates vanish but fermion susceptibilities diverge as non-trivial powers of the lattice size. We conjecture that this point may correspond to the condensation of certain topological defects which are generated from a higher order term in a derivative expansion of the fermion determinant. The existence of this higher order term is unique to the symmetries of the model