2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198898We employ a heat kernel expansion to derive an effective action that describes four dimensional SU(2) Yang-Mills theory in the infrared limit. Our result supports the proposal that at large distances the theory is approximated by the dynamics of knotted string-like fluxtubes which appear as solitons in the effective theory.4 pages, no figure, RevTexHigh Energy Physics - TheoryHigh Energy Physics - LatticeHigh Energy Physics - Phenomenologytext