  We present a numerical study about the confining regime of compact U(1)
lattice gauge theory in 4D. To address the problem, we exploit the duality
properties of the theory. The main features of this method are presented, and
its possible advantages and limits with respect to alternative techniques are
briefly discussed. In Monte Carlo simulations, we focus our attention onto the
case when a pair of static external charges is present. Some results are shown,
concerning different observables which are of interest in order to understand
the confinement mechanism, like the profile of the electric field induced by
the static charges, and the ratios between Polyakov loop correlation functions
at different distances.
