Glueballs in 3D QED with and without dynamical fermions

Measurements are presented of the glueball spectrum in 3D compact electrodynamics with and without dynamical fermions. The expected weak coupling behaviour of the pure gauge theory is observed for β > 1.5. In the coupling range studied, the predominant effect of dynamical fermions is accounted for by a shift in β of order 0.15 relative to the pure gauge theory. There is no evidence of dramatic mixing effects when light fermions are included in the glueball-mass calculations. Evidence is also presented for spontaneous breaking of a chiral symmetry in the quenched theory. In the full dynamical theory less convincing evidence is found. The relative efficiency of Langevin, microcanonical and Metropolis algorithms for generating independent configurations are discussed and two methods for extracting glueball masses are compared. (orig.)