2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198299Lattice studies of monopole condensation in QCD are based on the construction of a disorder parameter, a creation operator of monopoles which is written in terms of the gauge fields. This procedure is expected to work for any system which presents duality. We check it on the Ising model in 2d, which is exactly solvable. The output is an amusing exercise in statistical mechanics.14 pages, 3 figuresHigh Energy Physics - LatticeStatistical MechanicsHigh Energy Physics - Theorytext