Compact lattice U(1) and Seiberg–Witten duality

Simulations in compact U(1) lattice gauge theory in 4D show now beyond any reasonable doubts that the phase transition separating the Coulomb from the confined phase is of first order, albeit a very weak one. This settles the issue from the numerical side. On the analytical side, it was suggested some time ago, based on the qualitative analogy between the phase diagram of such a model and the one of scalar QED obtained by soft breaking the N=2 Seiberg–Witten model down to N=0, that the phase transition should be of second order. In this work we take a fresh look at this issue and show that a proper implementation of the Seiberg–Witten model below the supersymmetry breaking scale requires considering some new radiative corrections. Through the Coleman–Weinberg mechanism this turns the second-order transition into a weakly first-order one, in agreement with the numerical results. We comment on several other aspects of this continuum model.