We study the heavy charge potential in the Coulomb phase of pure gauge
compact U(1) theory on the lattice. We calculate the static potential
VW(T,R) from Wilson loops on a 163×32 lattice and compare
with the predictions of lattice perturbation theory. We investigate finite size
effects and, in particular, the importance of non-Coulomb contributions to the
potential. We also comment on the existence of a maximal coupling in the
Coulomb phase of pure gauge U(1) theory.Comment: 14 pages. LaTeX file and 3 postscript figure