2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42930We discuss the use of field theoretical techniques in the lattice determination of the free energy dependence on the $θ$ angle in SU(N) Yang-Mills theories.5 pages. Talk at the International Workshop on QCD: QCD@Work 2003 - Conversano (Italy) 14-18 June 2003 (eConf C030614)High Energy Physics - Phenomenologytext