Glueball Wave Functions in U(1) Lattice Gauge Theory

Standard Monte Carlo simulations have been performed for 3-dimensional U(1) lattice gauge model on improved lattices to measure the wavefunction and size of the scalar and the tensor glueballs. Our results show the radii of ~ 0.60 and ~ 1.12 in the units of string tension, or ~0.28 and ~0.52 fm, for the scalar and tensor glueballs, respectively. At finite temperature we see clear evidence of the deconfined phase, and the transition appears to be similar to that of the two-dimensional XY model as expected from universality arguments. Preliminary results show no significant changes in the glueball wave functions and the masses in the deconfined phase.