EXACT TOPOLOGICAL DENSITY IN THE LATTICE SKYRME MODEL

We propose using the Skyrme model on a lattice as an effective field theory of meson–baryon interactions. To this end we construct a local topological density that involves the volumes of tetrahedra in the target space S³ and we make use of Coxeter's formula for the Schläfli function to implement it. We calculate the mean-square radius of a skyrmion in the three-dimensional Skyrme model, and find some surprises.