The topological susceptibility of the 2D O(3) σ model

Abstract

We study the topological susceptibility, χ, of the 2D O(3) σ model by defining a density of topological charge as a local polynomial of the spin variables on the lattice. Following the field theoretical prescriptions we perform the additive and multiplicative renormalizations needed to extract χ from Monte Carlo data. By numerical simulations we show that the field theoretical definition and the cooling method give a consistent determination of χ.