Confinement/Deconfinement in 4D compact QED on the lattice.

It has long been known that there is a phase transition between confined and unconfined phases of compact pure gauge QED on the lattice. In this work we report three manifestations of this phase change as seen in the Landau gauge photon propagator, the static potential, and distribution of Dirac Strings in the gauge fixed configurations. Each of these was calculated with large lattices with volumes: $32^4$, $48^4$ and $96^4$. We show that the confined phase manifests with a Yukawa type propagator with a dynamically generated mass gap, a linearly increasing potential, and a significant concentration of Dirac strings while the unconfined phase appears consistent with the continuum results: a free propagator, a near constant long-distance potential, and a small concentration of Dirac strings trending towards zero. Furthermore, the photon propagator is investigated in detail near the transition between the two phases.