Electromagnetic self-duality in a lattice model

We formulate a Euclidean lattice theory of interacting elementary spin-half electric and magnetic charges, which we refer to as electrons and magnetic monopoles, respectively, The model uses the polymer representation of the fermion determinant, and exhibits a self-dual symmetry provided electric charge e and magnetic charge g obey the minimal Dirac quantisation condition eg = 2 pi. In a hopping parameter expansion at lowest order, we show that virtual electron and monopole loops contribute radiative corrections of opposite sign to the photon propagator, We argue that in the limit e --> 0, fermion mass mu --> 0, the model describes QED together with strongly interacting monopoles whose chiral symmetry is spontaneously broken, Prospect for the existence of an interacting continuum limit at the self-dual point e = g are discussed.