Chiral symmetry properties of U(1) lattice gauge theory with scalar and fermion fields

We report new results in three areas concerning the chiral transition in U(1) lattice gauge-Higgs theory with fermions. First, the case of a theory with two differently charged fermions simultaneously present is studied, and it is shown analytically that there are two associated continuous chiral phase transitions. Second, a general theorem is proved classifying the strong gauge-coupling behavior of any U(1) theory with a fermion and Higgs fields of arbitrary nonzero charges q_f and q_h: such a theory has a chiral transitions along the β_g = 0 line if and only if q_f is a nonzero multiple of q_h. Third, new data is presented on the chiral transition with quenched fermions in the interiof of the phase diagram at small or zero gauge-Higgs coupling, completing our earlier mapping of the chiral phase boundary.